merge: @main into client-integrity-verification

Reviewed-on: #45

.claude/memory/feedback_widget_decomposition.md

@@ -0,0 +1,11 @@
+---
+name: Widget decomposition and provider subscriptions
+description: Prefer splitting screens into multiple focused files/widgets; each widget subscribes to its own relevant providers
+type: feedback
+---
+
+Split screens into multiple smaller widgets across multiple files. Each widget should subscribe only to the providers it needs (`ref.watch` at lowest possible level), rather than having one large screen widget that watches everything and passes data down as parameters.
+
+**Why:** Reduces unnecessary rebuilds; improves readability; each file has one clear responsibility.
+
+**How to apply:** When building a new screen, identify which sub-widgets need their own provider subscriptions and extract them into separate files (e.g., `widgets/grant_card.dart` watches enrichment providers itself, rather than the screen doing it and passing resolved strings down).

.gitignore

@@ -2,3 +2,5 @@ target/
 scripts/__pycache__/
 .DS_Store
 .cargo/config.toml
+.vscode/
+docs/

.vscode/settings.json

@@ -1,2 +0,0 @@
-{
-}

.woodpecker/server-lint.yaml

@@ -22,4 +22,4 @@ steps:
       - apt-get update && apt-get install -y pkg-config
       - mise install rust 
       - mise install protoc
-      - mise exec rust -- cargo clippy --all-targets --all-features -- -D warnings
+      - mise exec rust -- cargo clippy --all -- -D warnings

.woodpecker/server-test.yaml

@@ -24,4 +24,4 @@ steps:
       - mise install rust 
       - mise install protoc
       - mise install cargo:cargo-nextest
-      - mise exec cargo:cargo-nextest -- cargo nextest run --no-fail-fast
+      - mise exec cargo:cargo-nextest -- cargo nextest run --no-fail-fast --all-features

.woodpecker/useragent-analyze.yaml

@@ -0,0 +1,18 @@
+when:
+  - event: pull_request
+    path:
+      include: ['.woodpecker/useragent-*.yaml', 'useragent/**']
+  - event: push
+    branch: main
+    path:
+      include: ['.woodpecker/useragent-*.yaml', 'useragent/**']
+
+steps:
+  - name: analyze
+    image: jdxcode/mise:latest
+    commands:
+      - mise install flutter 
+      - mise install protoc
+      # Reruns codegen to catch protocol drift
+      - mise codegen 
+      - cd useragent/ && flutter analyze

AGENTS.md

@@ -0,0 +1,128 @@
+# AGENTS.md
+
+This file provides guidance to Codex (Codex.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Arbiter is a **permissioned signing service** for cryptocurrency wallets. It consists of:
+- **`server/`** — Rust gRPC daemon that holds encrypted keys and enforces policies
+- **`useragent/`** — Flutter desktop app (macOS/Windows) with a Rust backend via Rinf
+- **`protobufs/`** — Protocol Buffer definitions shared between server and client
+
+The vault never exposes key material; it only produces signatures when requests satisfy configured policies.
+
+## Toolchain Setup
+
+Tools are managed via [mise](https://mise.jdx.dev/). Install all required tools:
+```sh
+mise install
+```
+
+Key versions: Rust 1.93.0 (with clippy), Flutter 3.38.9-stable, protoc 29.6, diesel_cli 2.3.6 (sqlite).
+
+## Server (Rust workspace at `server/`)
+
+### Crates
+
+| Crate | Purpose |
+|---|---|
+| `arbiter-proto` | Generated gRPC stubs + protobuf types; compiled from `protobufs/*.proto` via `tonic-prost-build` |
+| `arbiter-server` | Main daemon — actors, DB, EVM policy engine, gRPC service implementation |
+| `arbiter-useragent` | Rust client library for the user agent side of the gRPC protocol |
+| `arbiter-client` | Rust client library for SDK clients |
+
+### Common Commands
+
+```sh
+cd server
+
+# Build
+cargo build
+
+# Run the server daemon
+cargo run -p arbiter-server
+
+# Run all tests (preferred over cargo test)
+cargo nextest run
+
+# Run a single test
+cargo nextest run <test_name>
+
+# Lint
+cargo clippy
+
+# Security audit
+cargo audit
+
+# Check unused dependencies
+cargo shear
+
+# Run snapshot tests and update snapshots
+cargo insta review
+```
+
+### Architecture
+
+The server is actor-based using the **kameo** crate. All long-lived state lives in `GlobalActors`:
+
+- **`Bootstrapper`** — Manages the one-time bootstrap token written to `~/.arbiter/bootstrap_token` on first run.
+- **`KeyHolder`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
+- **`FlowCoordinator`** — Coordinates cross-connection flow between user agents and SDK clients.
+- **`EvmActor`** — Handles EVM transaction policy enforcement and signing.
+
+Per-connection actors live under `actors/user_agent/` and `actors/client/`, each with `auth` (challenge-response authentication) and `session` (post-auth operations) sub-modules.
+
+**Database:** SQLite via `diesel-async` + `bb8` connection pool. Schema managed by embedded Diesel migrations in `crates/arbiter-server/migrations/`. DB file lives at `~/.arbiter/arbiter.sqlite`. Tests use a temp-file DB via `db::create_test_pool()`.
+
+**Cryptography:**
+- Authentication: ed25519 (challenge-response, nonce-tracked per peer)
+- Encryption at rest: XChaCha20-Poly1305 (versioned via `scheme` field for transparent migration on unseal)
+- Password KDF: Argon2
+- Unseal transport: X25519 ephemeral key exchange
+- TLS: self-signed certificate (aws-lc-rs backend), fingerprint distributed via `ArbiterUrl`
+
+**Protocol:** gRPC with Protocol Buffers. The `ArbiterUrl` type encodes host, port, CA cert, and bootstrap token into a single shareable string (printed to console on first run).
+
+### Proto Regeneration
+
+When `.proto` files in `protobufs/` change, rebuild to regenerate:
+```sh
+cd server && cargo build -p arbiter-proto
+```
+
+### Database Migrations
+
+```sh
+# Create a new migration
+diesel migration generate <name> --migration-dir crates/arbiter-server/migrations
+
+# Run migrations manually (server also runs them on startup)
+diesel migration run --migration-dir crates/arbiter-server/migrations
+```
+
+## User Agent (Flutter + Rinf at `useragent/`)
+
+The Flutter app uses [Rinf](https://rinf.cunarist.org) to call Rust code. The Rust logic lives in `useragent/native/hub/` as a separate crate that uses `arbiter-useragent` for the gRPC client.
+
+Communication between Dart and Rust uses typed **signals** defined in `useragent/native/hub/src/signals/`. After modifying signal structs, regenerate Dart bindings:
+
+```sh
+cd useragent && rinf gen
+```
+
+### Common Commands
+
+```sh
+cd useragent
+
+# Run the app (macOS or Windows)
+flutter run
+
+# Regenerate Rust↔Dart signal bindings
+rinf gen
+
+# Analyze Dart code
+flutter analyze
+```
+
+The Rinf Rust entry point is `useragent/native/hub/src/lib.rs`. It spawns actors defined in `useragent/native/hub/src/actors/` which handle Dart↔server communication via signals.

CLAUDE.md

@@ -0,0 +1,128 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Arbiter is a **permissioned signing service** for cryptocurrency wallets. It consists of:
+- **`server/`** — Rust gRPC daemon that holds encrypted keys and enforces policies
+- **`useragent/`** — Flutter desktop app (macOS/Windows) with a Rust backend via Rinf
+- **`protobufs/`** — Protocol Buffer definitions shared between server and client
+
+The vault never exposes key material; it only produces signatures when requests satisfy configured policies.
+
+## Toolchain Setup
+
+Tools are managed via [mise](https://mise.jdx.dev/). Install all required tools:
+```sh
+mise install
+```
+
+Key versions: Rust 1.93.0 (with clippy), Flutter 3.38.9-stable, protoc 29.6, diesel_cli 2.3.6 (sqlite).
+
+## Server (Rust workspace at `server/`)
+
+### Crates
+
+| Crate | Purpose |
+|---|---|
+| `arbiter-proto` | Generated gRPC stubs + protobuf types; compiled from `protobufs/*.proto` via `tonic-prost-build` |
+| `arbiter-server` | Main daemon — actors, DB, EVM policy engine, gRPC service implementation |
+| `arbiter-useragent` | Rust client library for the user agent side of the gRPC protocol |
+| `arbiter-client` | Rust client library for SDK clients |
+
+### Common Commands
+
+```sh
+cd server
+
+# Build
+cargo build
+
+# Run the server daemon
+cargo run -p arbiter-server
+
+# Run all tests (preferred over cargo test)
+cargo nextest run
+
+# Run a single test
+cargo nextest run <test_name>
+
+# Lint
+cargo clippy
+
+# Security audit
+cargo audit
+
+# Check unused dependencies
+cargo shear
+
+# Run snapshot tests and update snapshots
+cargo insta review
+```
+
+### Architecture
+
+The server is actor-based using the **kameo** crate. All long-lived state lives in `GlobalActors`:
+
+- **`Bootstrapper`** — Manages the one-time bootstrap token written to `~/.arbiter/bootstrap_token` on first run.
+- **`KeyHolder`** — Holds the encrypted root key and manages the Sealed/Unsealed vault state machine. On unseal, decrypts the root key into a `memsafe` hardened memory cell.
+- **`FlowCoordinator`** — Coordinates cross-connection flow between user agents and SDK clients.
+- **`EvmActor`** — Handles EVM transaction policy enforcement and signing.
+
+Per-connection actors live under `actors/user_agent/` and `actors/client/`, each with `auth` (challenge-response authentication) and `session` (post-auth operations) sub-modules.
+
+**Database:** SQLite via `diesel-async` + `bb8` connection pool. Schema managed by embedded Diesel migrations in `crates/arbiter-server/migrations/`. DB file lives at `~/.arbiter/arbiter.sqlite`. Tests use a temp-file DB via `db::create_test_pool()`.
+
+**Cryptography:**
+- Authentication: ed25519 (challenge-response, nonce-tracked per peer)
+- Encryption at rest: XChaCha20-Poly1305 (versioned via `scheme` field for transparent migration on unseal)
+- Password KDF: Argon2
+- Unseal transport: X25519 ephemeral key exchange
+- TLS: self-signed certificate (aws-lc-rs backend), fingerprint distributed via `ArbiterUrl`
+
+**Protocol:** gRPC with Protocol Buffers. The `ArbiterUrl` type encodes host, port, CA cert, and bootstrap token into a single shareable string (printed to console on first run).
+
+### Proto Regeneration
+
+When `.proto` files in `protobufs/` change, rebuild to regenerate:
+```sh
+cd server && cargo build -p arbiter-proto
+```
+
+### Database Migrations
+
+```sh
+# Create a new migration
+diesel migration generate <name> --migration-dir crates/arbiter-server/migrations
+
+# Run migrations manually (server also runs them on startup)
+diesel migration run --migration-dir crates/arbiter-server/migrations
+```
+
+## User Agent (Flutter + Rinf at `useragent/`)
+
+The Flutter app uses [Rinf](https://rinf.cunarist.org) to call Rust code. The Rust logic lives in `useragent/native/hub/` as a separate crate that uses `arbiter-useragent` for the gRPC client.
+
+Communication between Dart and Rust uses typed **signals** defined in `useragent/native/hub/src/signals/`. After modifying signal structs, regenerate Dart bindings:
+
+```sh
+cd useragent && rinf gen
+```
+
+### Common Commands
+
+```sh
+cd useragent
+
+# Run the app (macOS or Windows)
+flutter run
+
+# Regenerate Rust↔Dart signal bindings
+rinf gen
+
+# Analyze Dart code
+flutter analyze
+```
+
+The Rinf Rust entry point is `useragent/native/hub/src/lib.rs`. It spawns actors defined in `useragent/native/hub/src/actors/` which handle Dart↔server communication via signals.

IMPLEMENTATION.md

@@ -6,6 +6,20 @@ This document covers concrete technology choices and dependencies. For the archi
 
 ## Client Connection Flow
 
+### Authentication Result Semantics
+
+Authentication no longer uses an implicit success-only response shape. Both `client` and `user-agent` return explicit auth status enums over the wire.
+
+- **Client:** `AuthResult` may return `SUCCESS`, `INVALID_KEY`, `INVALID_SIGNATURE`, `APPROVAL_DENIED`, `NO_USER_AGENTS_ONLINE`, or `INTERNAL`
+- **User-agent:** `AuthResult` may return `SUCCESS`, `INVALID_KEY`, `INVALID_SIGNATURE`, `BOOTSTRAP_REQUIRED`, `TOKEN_INVALID`, or `INTERNAL`
+
+This makes transport-level failures and actor/domain-level auth failures distinct:
+
+- **Transport/protocol failures** are surfaced as stream/status errors
+- **Authentication failures** are surfaced as successful protocol responses carrying an explicit auth status
+
+Clients are expected to handle these status codes directly and present the concrete failure reason to the user.
+
 ### New Client Approval
 
 When a client whose public key is not yet in the database connects, all connected user agents are asked to approve the connection. The first agent to respond determines the outcome; remaining requests are cancelled via a watch channel.
@@ -53,7 +67,18 @@ The `program_client.nonce` column stores the **next usable nonce** — i.e. it i
 ## Cryptography
 
 ### Authentication
-- **Signature scheme:** ed25519
+- **Client protocol:** ed25519
+
+### User-Agent Authentication
+
+User-agent authentication supports multiple signature schemes because platform-provided "hardware-bound" keys do not expose a uniform algorithm across operating systems and hardware.
+
+- **Supported schemes:** RSA, Ed25519, ECDSA (secp256k1)
+- **Why:** the user agent authenticates with keys backed by platform facilities, and those facilities differ by platform
+- **Apple Silicon Secure Enclave / Secure Element:** ECDSA-only in practice
+- **Windows Hello / TPM 2.0:** currently RSA-backed in our integration
+
+This is why the user-agent auth protocol carries an explicit `KeyType`, while the SDK client protocol remains fixed to ed25519.
 
 ### Encryption at Rest
 - **Scheme:** Symmetric AEAD — currently **XChaCha20-Poly1305**
@@ -68,9 +93,21 @@ The `program_client.nonce` column stores the **next usable nonce** — i.e. it i
 ## Communication
 
 - **Protocol:** gRPC with Protocol Buffers
+- **Request/response matching:** multiplexed over a single bidirectional stream using per-connection request IDs
 - **Server identity distribution:** `ServerInfo` protobuf struct containing the TLS public key fingerprint
 - **Future consideration:** grpc-web lacks bidirectional stream support, so a browser-based wallet may require protojson over WebSocket
 
+### Request Multiplexing
+
+Both `client` and `user-agent` connections support multiple in-flight requests over one gRPC bidi stream.
+
+- Every request carries a monotonically increasing request ID
+- Every normal response echoes the request ID it corresponds to
+- Out-of-band server messages omit the response ID entirely
+- The server rejects already-seen request IDs at the transport adapter boundary before business logic sees the message
+
+This keeps request correlation entirely in transport/client connection code while leaving actor and domain handlers unaware of request IDs.
+
 ---
 
 ## EVM Policy Engine
@@ -122,7 +159,7 @@ The central abstraction is the `Policy` trait. Each implementation handles one s
 Every grant has two layers:
 
 - **Shared (`evm_basic_grant`)** — wallet, chain, validity period, gas fee caps, transaction count rate limit. One row per grant regardless of type.
-- **Specific** — policy-owned tables (`evm_ether_transfer_grant`, `evm_token_transfer_grant`, etc.) holding type-specific configuration.
+- **Specific** — policy-owned tables (`evm_ether_transfer_grant`, `evm_token_transfer_grant`) holding type-specific configuration.
 
 `find_all_grants` uses a `#[diesel::auto_type]` base join between the specific and shared tables, then batch-loads related rows (targets, volume limits) in two additional queries to avoid N+1.
 
@@ -145,7 +182,6 @@ These are checked centrally in `check_shared_constraints` before policy evaluati
 - **Only EIP-1559 transactions are supported.** Legacy and EIP-2930 types are rejected outright.
 - **No opaque-calldata (unknown contract) grant type.** The architecture describes a category for unrecognised contracts, but no policy implements it yet. Any transaction that is not a plain ETH transfer or a known ERC-20 transfer is unconditionally rejected.
 - **Token registry is static.** Tokens are recognised only if they appear in the hard-coded `arbiter_tokens_registry` crate. There is no mechanism to register additional contracts at runtime.
-- **Nonce management is not implemented.** The architecture lists nonce deduplication as a core responsibility, but no nonce tracking or enforcement exists yet.
 
 ---
 
@@ -153,5 +189,5 @@ These are checked centrally in `check_shared_constraints` before policy evaluati
 
 The unsealed root key must be held in a hardened memory cell resistant to dumps, page swaps, and hibernation.
 
-- **Current:** Using the `memsafe` crate as an interim solution
+- **Current:** A dedicated memory-protection abstraction is in place, with `memsafe` used behind that abstraction today
-- **Planned:** Custom implementation based on `mlock` (Unix) and `VirtualProtect` (Windows)
+- **Planned:** Additional backends can be introduced behind the same abstraction, including a custom implementation based on `mlock` (Unix) and `VirtualProtect` (Windows)

docs/superpowers/plans/2026-03-28-grant-grid-view.md

@@ -0,0 +1,821 @@
+# Grant Grid View Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Add an "EVM Grants" dashboard tab that displays all grants as enriched cards (type, chain, wallet address, client name) with per-card revoke support.
+
+**Architecture:** A new `walletAccessListProvider` fetches wallet accesses with their DB row IDs. The screen (`grants.dart`) watches only `evmGrantsProvider` for top-level state. Each `GrantCard` widget (its own file) watches enrichment providers (`walletAccessListProvider`, `evmProvider`, `sdkClientsProvider`) and the revoke mutation directly — keeping rebuilds scoped to the card. The screen is registered as a dashboard tab in `AdaptiveScaffold`.
+
+**Tech Stack:** Flutter, Riverpod (`riverpod_annotation` + `build_runner` codegen), `sizer` (adaptive sizing), `auto_route`, Protocol Buffers (Dart), `Palette` design tokens.
+
+---
+
+## File Map
+
+| File | Action | Responsibility |
+|---|---|---|
+| `useragent/lib/theme/palette.dart` | Modify | Add `Palette.token` (indigo accent for token-transfer cards) |
+| `useragent/lib/features/connection/evm/wallet_access.dart` | Modify | Add `listAllWalletAccesses()` function |
+| `useragent/lib/providers/sdk_clients/wallet_access_list.dart` | Create | `WalletAccessListProvider` — fetches full wallet access list with IDs |
+| `useragent/lib/screens/dashboard/evm/grants/widgets/grant_card.dart` | Create | `GrantCard` widget — watches enrichment providers + revoke mutation; one card per grant |
+| `useragent/lib/screens/dashboard/evm/grants/grants.dart` | Create | `EvmGrantsScreen` — watches `evmGrantsProvider`; handles loading/error/empty/data states; renders `GrantCard` list |
+| `useragent/lib/router.dart` | Modify | Register `EvmGrantsRoute` in dashboard children |
+| `useragent/lib/screens/dashboard.dart` | Modify | Add Grants entry to `routes` list and `NavigationDestination` list |
+
+---
+
+## Task 1: Add `Palette.token`
+
+**Files:**
+- Modify: `useragent/lib/theme/palette.dart`
+
+- [ ] **Step 1: Add the color**
+
+Replace the contents of `useragent/lib/theme/palette.dart` with:
+
+```dart
+import 'package:flutter/material.dart';
+
+class Palette {
+  static const ink = Color(0xFF15263C);
+  static const coral = Color(0xFFE26254);
+  static const cream = Color(0xFFFFFAF4);
+  static const line = Color(0x1A15263C);
+  static const token = Color(0xFF5C6BC0);
+}
+```
+
+- [ ] **Step 2: Verify**
+
+```sh
+cd useragent && flutter analyze lib/theme/palette.dart
+```
+
+Expected: no issues.
+
+- [ ] **Step 3: Commit**
+
+```sh
+jj describe -m "feat(theme): add Palette.token for token-transfer grant cards"
+jj new
+```
+
+---
+
+## Task 2: Add `listAllWalletAccesses` feature function
+
+**Files:**
+- Modify: `useragent/lib/features/connection/evm/wallet_access.dart`
+
+`readClientWalletAccess` (existing) filters the list to one client's wallet IDs and returns `Set<int>`. This new function returns the complete unfiltered list with row IDs so the grant cards can resolve wallet_access_id → wallet + client.
+
+- [ ] **Step 1: Append function**
+
+Add at the bottom of `useragent/lib/features/connection/evm/wallet_access.dart`:
+
+```dart
+Future<List<SdkClientWalletAccess>> listAllWalletAccesses(
+  Connection connection,
+) async {
+  final response = await connection.ask(
+    UserAgentRequest(listWalletAccess: Empty()),
+  );
+  if (!response.hasListWalletAccessResponse()) {
+    throw Exception(
+      'Expected list wallet access response, got ${response.whichPayload()}',
+    );
+  }
+  return response.listWalletAccessResponse.accesses.toList(growable: false);
+}
+```
+
+Each returned `SdkClientWalletAccess` has:
+- `.id` — the `evm_wallet_access` row ID (same value as `wallet_access_id` in a `GrantEntry`)
+- `.access.walletId` — the EVM wallet DB ID
+- `.access.sdkClientId` — the SDK client DB ID
+
+- [ ] **Step 2: Verify**
+
+```sh
+cd useragent && flutter analyze lib/features/connection/evm/wallet_access.dart
+```
+
+Expected: no issues.
+
+- [ ] **Step 3: Commit**
+
+```sh
+jj describe -m "feat(evm): add listAllWalletAccesses feature function"
+jj new
+```
+
+---
+
+## Task 3: Create `WalletAccessListProvider`
+
+**Files:**
+- Create: `useragent/lib/providers/sdk_clients/wallet_access_list.dart`
+- Generated: `useragent/lib/providers/sdk_clients/wallet_access_list.g.dart`
+
+Mirrors the structure of `EvmGrants` in `providers/evm/evm_grants.dart` — class-based `@riverpod` with a `refresh()` method.
+
+- [ ] **Step 1: Write the provider**
+
+Create `useragent/lib/providers/sdk_clients/wallet_access_list.dart`:
+
+```dart
+import 'package:arbiter/features/connection/evm/wallet_access.dart';
+import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:arbiter/providers/connection/connection_manager.dart';
+import 'package:mtcore/markettakers.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+part 'wallet_access_list.g.dart';
+
+@riverpod
+class WalletAccessList extends _$WalletAccessList {
+  @override
+  Future<List<SdkClientWalletAccess>?> build() async {
+    final connection = await ref.watch(connectionManagerProvider.future);
+    if (connection == null) {
+      return null;
+    }
+
+    try {
+      return await listAllWalletAccesses(connection);
+    } catch (e, st) {
+      talker.handle(e, st);
+      rethrow;
+    }
+  }
+
+  Future<void> refresh() async {
+    final connection = await ref.read(connectionManagerProvider.future);
+    if (connection == null) {
+      state = const AsyncData(null);
+      return;
+    }
+
+    state = const AsyncLoading();
+    state = await AsyncValue.guard(() => listAllWalletAccesses(connection));
+  }
+}
+```
+
+- [ ] **Step 2: Run code generation**
+
+```sh
+cd useragent && dart run build_runner build --delete-conflicting-outputs
+```
+
+Expected: `useragent/lib/providers/sdk_clients/wallet_access_list.g.dart` created. No errors.
+
+- [ ] **Step 3: Verify**
+
+```sh
+cd useragent && flutter analyze lib/providers/sdk_clients/
+```
+
+Expected: no issues.
+
+- [ ] **Step 4: Commit**
+
+```sh
+jj describe -m "feat(providers): add WalletAccessListProvider"
+jj new
+```
+
+---
+
+## Task 4: Create `GrantCard` widget
+
+**Files:**
+- Create: `useragent/lib/screens/dashboard/evm/grants/widgets/grant_card.dart`
+
+This widget owns all per-card logic: enrichment lookups, revoke action, and rebuild scope. The screen only passes it a `GrantEntry` — the card fetches everything else itself.
+
+**Key types:**
+- `GrantEntry` (from `proto/evm.pb.dart`): `.id`, `.shared.walletAccessId`, `.shared.chainId`, `.specific.whichGrant()`
+- `SpecificGrant_Grant.etherTransfer` / `.tokenTransfer` — enum values for the oneof
+- `SdkClientWalletAccess` (from `proto/user_agent.pb.dart`): `.id`, `.access.walletId`, `.access.sdkClientId`
+- `WalletEntry` (from `proto/evm.pb.dart`): `.id`, `.address` (List<int>)
+- `SdkClientEntry` (from `proto/user_agent.pb.dart`): `.id`, `.info.name`
+- `revokeEvmGrantMutation` — `Mutation<void>` (global; all revoke buttons disable together while any revoke is in flight)
+- `executeRevokeEvmGrant(ref, grantId: int)` — `Future<void>`
+
+- [ ] **Step 1: Write the widget**
+
+Create `useragent/lib/screens/dashboard/evm/grants/widgets/grant_card.dart`:
+
+```dart
+import 'package:arbiter/proto/evm.pb.dart';
+import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:arbiter/providers/evm/evm.dart';
+import 'package:arbiter/providers/evm/evm_grants.dart';
+import 'package:arbiter/providers/sdk_clients/list.dart';
+import 'package:arbiter/providers/sdk_clients/wallet_access_list.dart';
+import 'package:arbiter/theme/palette.dart';
+import 'package:flutter/material.dart';
+import 'package:hooks_riverpod/experimental/mutation.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:sizer/sizer.dart';
+
+String _shortAddress(List<int> bytes) {
+  final hex = bytes.map((b) => b.toRadixString(16).padLeft(2, '0')).join();
+  return '0x${hex.substring(0, 6)}...${hex.substring(hex.length - 4)}';
+}
+
+String _formatError(Object error) {
+  final message = error.toString();
+  if (message.startsWith('Exception: ')) {
+    return message.substring('Exception: '.length);
+  }
+  return message;
+}
+
+class GrantCard extends ConsumerWidget {
+  const GrantCard({super.key, required this.grant});
+
+  final GrantEntry grant;
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    // Enrichment lookups — each watch scopes rebuilds to this card only
+    final walletAccesses =
+        ref.watch(walletAccessListProvider).asData?.value ?? const [];
+    final wallets = ref.watch(evmProvider).asData?.value ?? const [];
+    final clients = ref.watch(sdkClientsProvider).asData?.value ?? const [];
+    final revoking = ref.watch(revokeEvmGrantMutation) is MutationPending;
+
+    final isEther =
+        grant.specific.whichGrant() == SpecificGrant_Grant.etherTransfer;
+    final accent = isEther ? Palette.coral : Palette.token;
+    final typeLabel = isEther ? 'Ether' : 'Token';
+    final theme = Theme.of(context);
+    final muted = Palette.ink.withValues(alpha: 0.62);
+
+    // Resolve wallet_access_id → wallet address + client name
+    final accessById = <int, SdkClientWalletAccess>{
+      for (final a in walletAccesses) a.id: a,
+    };
+    final walletById = <int, WalletEntry>{
+      for (final w in wallets) w.id: w,
+    };
+    final clientNameById = <int, String>{
+      for (final c in clients) c.id: c.info.name,
+    };
+
+    final accessId = grant.shared.walletAccessId;
+    final access = accessById[accessId];
+    final wallet = access != null ? walletById[access.access.walletId] : null;
+
+    final walletLabel = wallet != null
+        ? _shortAddress(wallet.address)
+        : 'Access #$accessId';
+
+    final clientLabel = () {
+      if (access == null) return '';
+      final name = clientNameById[access.access.sdkClientId] ?? '';
+      return name.isEmpty ? 'Client #${access.access.sdkClientId}' : name;
+    }();
+
+    void showError(String message) {
+      if (!context.mounted) return;
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text(message), behavior: SnackBarBehavior.floating),
+      );
+    }
+
+    Future<void> revoke() async {
+      try {
+        await executeRevokeEvmGrant(ref, grantId: grant.id);
+      } catch (e) {
+        showError(_formatError(e));
+      }
+    }
+
+    return Container(
+      decoration: BoxDecoration(
+        borderRadius: BorderRadius.circular(24),
+        color: Palette.cream.withValues(alpha: 0.92),
+        border: Border.all(color: Palette.line),
+      ),
+      child: IntrinsicHeight(
+        child: Row(
+          crossAxisAlignment: CrossAxisAlignment.stretch,
+          children: [
+            // Accent strip
+            Container(
+              width: 0.8.w,
+              decoration: BoxDecoration(
+                color: accent,
+                borderRadius: const BorderRadius.horizontal(
+                  left: Radius.circular(24),
+                ),
+              ),
+            ),
+            // Card body
+            Expanded(
+              child: Padding(
+                padding: EdgeInsets.symmetric(
+                  horizontal: 1.6.w,
+                  vertical: 1.4.h,
+                ),
+                child: Column(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  children: [
+                    // Row 1: type badge · chain · spacer · revoke button
+                    Row(
+                      children: [
+                        Container(
+                          padding: EdgeInsets.symmetric(
+                            horizontal: 1.w,
+                            vertical: 0.4.h,
+                          ),
+                          decoration: BoxDecoration(
+                            color: accent.withValues(alpha: 0.15),
+                            borderRadius: BorderRadius.circular(8),
+                          ),
+                          child: Text(
+                            typeLabel,
+                            style: theme.textTheme.labelSmall?.copyWith(
+                              color: accent,
+                              fontWeight: FontWeight.w800,
+                            ),
+                          ),
+                        ),
+                        SizedBox(width: 1.w),
+                        Container(
+                          padding: EdgeInsets.symmetric(
+                            horizontal: 1.w,
+                            vertical: 0.4.h,
+                          ),
+                          decoration: BoxDecoration(
+                            color: Palette.ink.withValues(alpha: 0.06),
+                            borderRadius: BorderRadius.circular(8),
+                          ),
+                          child: Text(
+                            'Chain ${grant.shared.chainId}',
+                            style: theme.textTheme.labelSmall?.copyWith(
+                              color: muted,
+                              fontWeight: FontWeight.w700,
+                            ),
+                          ),
+                        ),
+                        const Spacer(),
+                        if (revoking)
+                          SizedBox(
+                            width: 1.8.h,
+                            height: 1.8.h,
+                            child: CircularProgressIndicator(
+                              strokeWidth: 2,
+                              color: Palette.coral,
+                            ),
+                          )
+                        else
+                          OutlinedButton.icon(
+                            onPressed: revoke,
+                            style: OutlinedButton.styleFrom(
+                              foregroundColor: Palette.coral,
+                              side: BorderSide(
+                                color: Palette.coral.withValues(alpha: 0.4),
+                              ),
+                              padding: EdgeInsets.symmetric(
+                                horizontal: 1.w,
+                                vertical: 0.6.h,
+                              ),
+                              shape: RoundedRectangleBorder(
+                                borderRadius: BorderRadius.circular(10),
+                              ),
+                            ),
+                            icon: const Icon(Icons.block_rounded, size: 16),
+                            label: const Text('Revoke'),
+                          ),
+                      ],
+                    ),
+                    SizedBox(height: 0.8.h),
+                    // Row 2: wallet address · client name
+                    Row(
+                      children: [
+                        Text(
+                          walletLabel,
+                          style: theme.textTheme.bodySmall?.copyWith(
+                            color: Palette.ink,
+                            fontFamily: 'monospace',
+                          ),
+                        ),
+                        Padding(
+                          padding: EdgeInsets.symmetric(horizontal: 0.8.w),
+                          child: Text(
+                            '·',
+                            style: theme.textTheme.bodySmall
+                                ?.copyWith(color: muted),
+                          ),
+                        ),
+                        Expanded(
+                          child: Text(
+                            clientLabel,
+                            maxLines: 1,
+                            overflow: TextOverflow.ellipsis,
+                            style: theme.textTheme.bodySmall
+                                ?.copyWith(color: muted),
+                          ),
+                        ),
+                      ],
+                    ),
+                  ],
+                ),
+              ),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}
+```
+
+- [ ] **Step 2: Verify**
+
+```sh
+cd useragent && flutter analyze lib/screens/dashboard/evm/grants/widgets/grant_card.dart
+```
+
+Expected: no issues.
+
+- [ ] **Step 3: Commit**
+
+```sh
+jj describe -m "feat(grants): add GrantCard widget with self-contained enrichment"
+jj new
+```
+
+---
+
+## Task 5: Create `EvmGrantsScreen`
+
+**Files:**
+- Create: `useragent/lib/screens/dashboard/evm/grants/grants.dart`
+
+The screen watches only `evmGrantsProvider` for top-level state (loading / error / no connection / empty / data). When there is data it renders a list of `GrantCard` widgets — each card manages its own enrichment subscriptions.
+
+- [ ] **Step 1: Write the screen**
+
+Create `useragent/lib/screens/dashboard/evm/grants/grants.dart`:
+
+```dart
+import 'package:arbiter/proto/evm.pb.dart';
+import 'package:arbiter/providers/evm/evm_grants.dart';
+import 'package:arbiter/providers/sdk_clients/wallet_access_list.dart';
+import 'package:arbiter/router.gr.dart';
+import 'package:arbiter/screens/dashboard/evm/grants/widgets/grant_card.dart';
+import 'package:arbiter/theme/palette.dart';
+import 'package:arbiter/widgets/page_header.dart';
+import 'package:auto_route/auto_route.dart';
+import 'package:flutter/material.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:sizer/sizer.dart';
+
+String _formatError(Object error) {
+  final message = error.toString();
+  if (message.startsWith('Exception: ')) {
+    return message.substring('Exception: '.length);
+  }
+  return message;
+}
+
+// ─── State panel ──────────────────────────────────────────────────────────────
+
+class _StatePanel extends StatelessWidget {
+  const _StatePanel({
+    required this.icon,
+    required this.title,
+    required this.body,
+    this.actionLabel,
+    this.onAction,
+    this.busy = false,
+  });
+
+  final IconData icon;
+  final String title;
+  final String body;
+  final String? actionLabel;
+  final Future<void> Function()? onAction;
+  final bool busy;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+
+    return Container(
+      decoration: BoxDecoration(
+        borderRadius: BorderRadius.circular(24),
+        color: Palette.cream.withValues(alpha: 0.92),
+        border: Border.all(color: Palette.line),
+      ),
+      child: Padding(
+        padding: EdgeInsets.all(2.8.h),
+        child: Column(
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            if (busy)
+              SizedBox(
+                width: 2.8.h,
+                height: 2.8.h,
+                child: const CircularProgressIndicator(strokeWidth: 2.5),
+              )
+            else
+              Icon(icon, size: 34, color: Palette.coral),
+            SizedBox(height: 1.8.h),
+            Text(
+              title,
+              style: theme.textTheme.headlineSmall?.copyWith(
+                color: Palette.ink,
+                fontWeight: FontWeight.w800,
+              ),
+            ),
+            SizedBox(height: 1.h),
+            Text(
+              body,
+              style: theme.textTheme.bodyLarge?.copyWith(
+                color: Palette.ink.withValues(alpha: 0.72),
+                height: 1.5,
+              ),
+            ),
+            if (actionLabel != null && onAction != null) ...[
+              SizedBox(height: 2.h),
+              OutlinedButton.icon(
+                onPressed: () => onAction!(),
+                icon: const Icon(Icons.refresh),
+                label: Text(actionLabel!),
+              ),
+            ],
+          ],
+        ),
+      ),
+    );
+  }
+}
+
+// ─── Grant list ───────────────────────────────────────────────────────────────
+
+class _GrantList extends StatelessWidget {
+  const _GrantList({required this.grants});
+
+  final List<GrantEntry> grants;
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      children: [
+        for (var i = 0; i < grants.length; i++)
+          Padding(
+            padding: EdgeInsets.only(
+              bottom: i == grants.length - 1 ? 0 : 1.8.h,
+            ),
+            child: GrantCard(grant: grants[i]),
+          ),
+      ],
+    );
+  }
+}
+
+// ─── Screen ───────────────────────────────────────────────────────────────────
+
+@RoutePage()
+class EvmGrantsScreen extends ConsumerWidget {
+  const EvmGrantsScreen({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    // Screen watches only the grant list for top-level state decisions
+    final grantsAsync = ref.watch(evmGrantsProvider);
+
+    Future<void> refresh() async {
+      await Future.wait([
+        ref.read(evmGrantsProvider.notifier).refresh(),
+        ref.read(walletAccessListProvider.notifier).refresh(),
+      ]);
+    }
+
+    void showMessage(String message) {
+      if (!context.mounted) return;
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text(message), behavior: SnackBarBehavior.floating),
+      );
+    }
+
+    Future<void> safeRefresh() async {
+      try {
+        await refresh();
+      } catch (e) {
+        showMessage(_formatError(e));
+      }
+    }
+
+    final grantsState = grantsAsync.asData?.value;
+    final grants = grantsState?.grants;
+
+    final content = switch (grantsAsync) {
+      AsyncLoading() when grantsState == null => const _StatePanel(
+        icon: Icons.hourglass_top,
+        title: 'Loading grants',
+        body: 'Pulling grant registry from Arbiter.',
+        busy: true,
+      ),
+      AsyncError(:final error) => _StatePanel(
+        icon: Icons.sync_problem,
+        title: 'Grant registry unavailable',
+        body: _formatError(error),
+        actionLabel: 'Retry',
+        onAction: safeRefresh,
+      ),
+      AsyncData(:final value) when value == null => _StatePanel(
+        icon: Icons.portable_wifi_off,
+        title: 'No active server connection',
+        body: 'Reconnect to Arbiter to list EVM grants.',
+        actionLabel: 'Refresh',
+        onAction: safeRefresh,
+      ),
+      _ when grants != null && grants.isEmpty => _StatePanel(
+        icon: Icons.policy_outlined,
+        title: 'No grants yet',
+        body: 'Create a grant to allow SDK clients to sign transactions.',
+        actionLabel: 'Create grant',
+        onAction: () => context.router.push(const CreateEvmGrantRoute()),
+      ),
+      _ => _GrantList(grants: grants ?? const []),
+    };
+
+    return Scaffold(
+      body: SafeArea(
+        child: RefreshIndicator.adaptive(
+          color: Palette.ink,
+          backgroundColor: Colors.white,
+          onRefresh: safeRefresh,
+          child: ListView(
+            physics: const BouncingScrollPhysics(
+              parent: AlwaysScrollableScrollPhysics(),
+            ),
+            padding: EdgeInsets.fromLTRB(2.4.w, 2.4.h, 2.4.w, 3.2.h),
+            children: [
+              PageHeader(
+                title: 'EVM Grants',
+                isBusy: grantsAsync.isLoading,
+                actions: [
+                  FilledButton.icon(
+                    onPressed: () =>
+                        context.router.push(const CreateEvmGrantRoute()),
+                    icon: const Icon(Icons.add_rounded),
+                    label: const Text('Create grant'),
+                  ),
+                  SizedBox(width: 1.w),
+                  OutlinedButton.icon(
+                    onPressed: safeRefresh,
+                    style: OutlinedButton.styleFrom(
+                      foregroundColor: Palette.ink,
+                      side: BorderSide(color: Palette.line),
+                      padding: EdgeInsets.symmetric(
+                        horizontal: 1.4.w,
+                        vertical: 1.2.h,
+                      ),
+                      shape: RoundedRectangleBorder(
+                        borderRadius: BorderRadius.circular(14),
+                      ),
+                    ),
+                    icon: const Icon(Icons.refresh, size: 18),
+                    label: const Text('Refresh'),
+                  ),
+                ],
+              ),
+              SizedBox(height: 1.8.h),
+              content,
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}
+```
+
+- [ ] **Step 2: Verify**
+
+```sh
+cd useragent && flutter analyze lib/screens/dashboard/evm/grants/
+```
+
+Expected: no issues.
+
+- [ ] **Step 3: Commit**
+
+```sh
+jj describe -m "feat(grants): add EvmGrantsScreen"
+jj new
+```
+
+---
+
+## Task 6: Wire router and dashboard tab
+
+**Files:**
+- Modify: `useragent/lib/router.dart`
+- Modify: `useragent/lib/screens/dashboard.dart`
+- Regenerated: `useragent/lib/router.gr.dart`
+
+- [ ] **Step 1: Add route to `router.dart`**
+
+Replace the contents of `useragent/lib/router.dart` with:
+
+```dart
+import 'package:auto_route/auto_route.dart';
+
+import 'router.gr.dart';
+
+@AutoRouterConfig(generateForDir: ['lib/screens'])
+class Router extends RootStackRouter {
+  @override
+  List<AutoRoute> get routes => [
+    AutoRoute(page: Bootstrap.page, path: '/bootstrap', initial: true),
+    AutoRoute(page: ServerInfoSetupRoute.page, path: '/server-info'),
+    AutoRoute(page: ServerConnectionRoute.page, path: '/server-connection'),
+    AutoRoute(page: VaultSetupRoute.page, path: '/vault'),
+    AutoRoute(page: ClientDetailsRoute.page, path: '/clients/:clientId'),
+    AutoRoute(page: CreateEvmGrantRoute.page, path: '/evm-grants/create'),
+
+    AutoRoute(
+      page: DashboardRouter.page,
+      path: '/dashboard',
+      children: [
+        AutoRoute(page: EvmRoute.page, path: 'evm'),
+        AutoRoute(page: ClientsRoute.page, path: 'clients'),
+        AutoRoute(page: EvmGrantsRoute.page, path: 'grants'),
+        AutoRoute(page: AboutRoute.page, path: 'about'),
+      ],
+    ),
+  ];
+}
+```
+
+- [ ] **Step 2: Update `dashboard.dart`**
+
+In `useragent/lib/screens/dashboard.dart`, replace the `routes` constant:
+
+```dart
+final routes = [
+  const EvmRoute(),
+  const ClientsRoute(),
+  const EvmGrantsRoute(),
+  const AboutRoute(),
+];
+```
+
+And replace the `destinations` list inside `AdaptiveScaffold`:
+
+```dart
+destinations: const [
+  NavigationDestination(
+    icon: Icon(Icons.account_balance_wallet_outlined),
+    selectedIcon: Icon(Icons.account_balance_wallet),
+    label: 'Wallets',
+  ),
+  NavigationDestination(
+    icon: Icon(Icons.devices_other_outlined),
+    selectedIcon: Icon(Icons.devices_other),
+    label: 'Clients',
+  ),
+  NavigationDestination(
+    icon: Icon(Icons.policy_outlined),
+    selectedIcon: Icon(Icons.policy),
+    label: 'Grants',
+  ),
+  NavigationDestination(
+    icon: Icon(Icons.info_outline),
+    selectedIcon: Icon(Icons.info),
+    label: 'About',
+  ),
+],
+```
+
+- [ ] **Step 3: Regenerate router**
+
+```sh
+cd useragent && dart run build_runner build --delete-conflicting-outputs
+```
+
+Expected: `lib/router.gr.dart` updated, `EvmGrantsRoute` now available, no errors.
+
+- [ ] **Step 4: Full project verify**
+
+```sh
+cd useragent && flutter analyze
+```
+
+Expected: no issues.
+
+- [ ] **Step 5: Commit**
+
+```sh
+jj describe -m "feat(nav): add Grants dashboard tab"
+jj new
+```

docs/superpowers/specs/2026-03-28-grant-grid-view-design.md

@@ -0,0 +1,170 @@
+# Grant Grid View — Design Spec
+
+**Date:** 2026-03-28
+
+## Overview
+
+Add a "Grants" dashboard tab to the Flutter user-agent app that displays all EVM grants as a card-based grid. Each card shows a compact summary (type, chain, wallet address, client name) with a revoke action. The tab integrates into the existing `AdaptiveScaffold` navigation alongside Wallets, Clients, and About.
+
+## Scope
+
+- New `walletAccessListProvider` for fetching wallet access entries with their DB row IDs
+- New `EvmGrantsScreen` as a dashboard tab
+- Grant card widget with enriched display (type, chain, wallet, client)
+- Revoke action wired to existing `executeRevokeEvmGrant` mutation
+- Dashboard tab bar and router updated
+- New token-transfer accent color added to `Palette`
+
+**Out of scope:** Fixing grant creation (separate task).
+
+---
+
+## Data Layer
+
+### `walletAccessListProvider`
+
+**File:** `useragent/lib/providers/sdk_clients/wallet_access_list.dart`
+
+- `@riverpod` class, watches `connectionManagerProvider.future`
+- Returns `List<SdkClientWalletAccess>?` (null when not connected)
+- Each entry: `.id` (wallet_access_id), `.access.walletId`, `.access.sdkClientId`
+- Exposes a `refresh()` method following the same pattern as `EvmGrants.refresh()`
+
+### Enrichment at render time (Approach A)
+
+The `EvmGrantsScreen` watches four providers:
+1. `evmGrantsProvider` — the grant list
+2. `walletAccessListProvider` — to resolve wallet_access_id → (wallet_id, sdk_client_id)
+3. `evmProvider` — to resolve wallet_id → wallet address
+4. `sdkClientsProvider` — to resolve sdk_client_id → client name
+
+All lookups are in-memory Maps built inside the build method; no extra model class needed.
+
+Fallbacks:
+- Wallet address not found → `"Access #N"` where N is the wallet_access_id
+- Client name not found → `"Client #N"` where N is the sdk_client_id
+
+---
+
+## Route Structure
+
+```
+/dashboard
+  /evm          ← existing (Wallets tab)
+  /clients      ← existing (Clients tab)
+  /grants       ← NEW (Grants tab)
+  /about        ← existing
+
+/evm-grants/create  ← existing push route (unchanged)
+```
+
+### Changes to `router.dart`
+
+Add inside dashboard children:
+```dart
+AutoRoute(page: EvmGrantsRoute.page, path: 'grants'),
+```
+
+### Changes to `dashboard.dart`
+
+Add to `routes` list:
+```dart
+const EvmGrantsRoute()
+```
+
+Add `NavigationDestination`:
+```dart
+NavigationDestination(
+  icon: Icon(Icons.policy_outlined),
+  selectedIcon: Icon(Icons.policy),
+  label: 'Grants',
+),
+```
+
+---
+
+## Screen: `EvmGrantsScreen`
+
+**File:** `useragent/lib/screens/dashboard/evm/grants/grants.dart`
+
+```
+Scaffold
+└─ SafeArea
+   └─ RefreshIndicator.adaptive (refreshes evmGrantsProvider + walletAccessListProvider)
+      └─ ListView (BouncingScrollPhysics + AlwaysScrollableScrollPhysics)
+         ├─ PageHeader
+         │    title: 'EVM Grants'
+         │    isBusy: evmGrantsProvider.isLoading
+         │    actions: [CreateGrantButton, RefreshButton]
+         ├─ SizedBox(height: 1.8.h)
+         └─ <content>
+```
+
+### State handling
+
+Matches the pattern from `EvmScreen` and `ClientsScreen`:
+
+| State | Display |
+|---|---|
+| Loading (no data yet) | `_StatePanel` with spinner, "Loading grants" |
+| Error | `_StatePanel` with coral icon, error message, Retry button |
+| No connection | `_StatePanel`, "No active server connection" |
+| Empty list | `_StatePanel`, "No grants yet", with Create Grant shortcut |
+| Data | Column of `_GrantCard` widgets |
+
+### Header actions
+
+**CreateGrantButton:** `FilledButton.icon` with `Icons.add_rounded`, pushes `CreateEvmGrantRoute()` via `context.router.push(...)`.
+
+**RefreshButton:** `OutlinedButton.icon` with `Icons.refresh`, calls `ref.read(evmGrantsProvider.notifier).refresh()`.
+
+---
+
+## Grant Card: `_GrantCard`
+
+**Layout:**
+
+```
+Container (rounded 24, Palette.cream bg, Palette.line border)
+└─ IntrinsicHeight > Row
+   ├─ Accent strip (0.8.w wide, full height, rounded left)
+   └─ Padding > Column
+        ├─ Row 1: TypeBadge + ChainChip + Spacer + RevokeButton
+        └─ Row 2: WalletText + "·" + ClientText
+```
+
+**Accent color by grant type:**
+- Ether transfer → `Palette.coral`
+- Token transfer → `Palette.token` (new entry in `Palette` — indigo, e.g. `Color(0xFF5C6BC0)`)
+
+**TypeBadge:** Small pill container with accent color background at 15% opacity, accent-colored text. Label: `'Ether'` or `'Token'`.
+
+**ChainChip:** Small container: `'Chain ${grant.shared.chainId}'`, muted ink color.
+
+**WalletText:** Short hex address (`0xabc...def`) from wallet lookup, `bodySmall`, monospace font family.
+
+**ClientText:** Client name from `sdkClientsProvider` lookup, or fallback string. `bodySmall`, muted ink.
+
+**RevokeButton:**
+- `OutlinedButton` with `Icons.block_rounded` icon, label `'Revoke'`
+- `foregroundColor: Palette.coral`, `side: BorderSide(color: Palette.coral.withValues(alpha: 0.4))`
+- Disabled (replaced with `CircularProgressIndicator`) while `revokeEvmGrantMutation` is pending — note: this is a single global mutation, so all revoke buttons disable while any revoke is in flight
+- On press: calls `executeRevokeEvmGrant(ref, grantId: grant.id)`; shows `SnackBar` on error
+
+---
+
+## Adaptive Sizing
+
+All sizing uses `sizer` units (`1.h`, `1.w`, etc.). No hardcoded pixel values.
+
+---
+
+## Files to Create / Modify
+
+| File | Action |
+|---|---|
+| `lib/theme/palette.dart` | Modify — add `Palette.token` color |
+| `lib/providers/sdk_clients/wallet_access_list.dart` | Create |
+| `lib/screens/dashboard/evm/grants/grants.dart` | Create |
+| `lib/router.dart` | Modify — add grants route to dashboard children |
+| `lib/screens/dashboard.dart` | Modify — add tab to routes list and NavigationDestinations |

mise.lock

@@ -1,10 +1,44 @@
+# @generated - this file is auto-generated by `mise lock` https://mise.jdx.dev/dev-tools/mise-lock.html
+
+[[tools.ast-grep]]
+version = "0.42.0"
+backend = "aqua:ast-grep/ast-grep"
+
+[tools.ast-grep."platforms.linux-arm64"]
+checksum = "sha256:5c830eae8456569e2f7212434ed9c238f58dca412d76045418ed6d394a755836"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-aarch64-unknown-linux-gnu.zip"
+
+[tools.ast-grep."platforms.linux-arm64-musl"]
+checksum = "sha256:5c830eae8456569e2f7212434ed9c238f58dca412d76045418ed6d394a755836"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-aarch64-unknown-linux-gnu.zip"
+
+[tools.ast-grep."platforms.linux-x64"]
+checksum = "sha256:e825a05603f0bcc4cd9076c4cc8c9abd6d008b7cd07d9aa3cc323ba4b8606651"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-x86_64-unknown-linux-gnu.zip"
+
+[tools.ast-grep."platforms.linux-x64-musl"]
+checksum = "sha256:e825a05603f0bcc4cd9076c4cc8c9abd6d008b7cd07d9aa3cc323ba4b8606651"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-x86_64-unknown-linux-gnu.zip"
+
+[tools.ast-grep."platforms.macos-arm64"]
+checksum = "sha256:fc300d5293b1c770a5aece03a8a193b92e71e87cec726c28096990691a582620"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-aarch64-apple-darwin.zip"
+
+[tools.ast-grep."platforms.macos-x64"]
+checksum = "sha256:979ffe611327056f4730a1ae71b0209b3b830f58b22c6ed194cda34f55400db2"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-x86_64-apple-darwin.zip"
+
+[tools.ast-grep."platforms.windows-x64"]
+checksum = "sha256:55836fa1b2c65dc7d61615a4d9368622a0d2371a76d28b9a165e5a3ab6ae32a4"
+url = "https://github.com/ast-grep/ast-grep/releases/download/0.42.0/app-x86_64-pc-windows-msvc.zip"
+
 [[tools."cargo:cargo-audit"]]
 version = "0.22.1"
 backend = "cargo:cargo-audit"
 
-[[tools."cargo:cargo-features"]]
+[[tools."cargo:cargo-edit"]]
-version = "1.0.0"
+version = "0.13.9"
-backend = "cargo:cargo-features"
+backend = "cargo:cargo-edit"
 
 [[tools."cargo:cargo-features-manager"]]
 version = "0.11.1"
@@ -19,21 +53,13 @@ version = "0.9.126"
 backend = "cargo:cargo-nextest"
 
 [[tools."cargo:cargo-shear"]]
-version = "1.9.1"
+version = "1.11.2"
 backend = "cargo:cargo-shear"
 
 [[tools."cargo:cargo-vet"]]
 version = "0.10.2"
 backend = "cargo:cargo-vet"
 
-[[tools."cargo:diesel-cli"]]
-version = "2.3.6"
-backend = "cargo:diesel-cli"
-
-[tools."cargo:diesel-cli".options]
-default-features = "false"
-features = "sqlite,sqlite-bundled"
-
 [[tools."cargo:diesel_cli"]]
 version = "2.3.6"
 backend = "cargo:diesel_cli"
@@ -49,20 +75,66 @@ backend = "asdf:flutter"
 [[tools.protoc]]
 version = "29.6"
 backend = "aqua:protocolbuffers/protobuf/protoc"
-"platforms.linux-arm64" = { checksum = "sha256:2594ff4fcae8cb57310d394d0961b236190ad9c5efbfdf1f597ea471d424fe79", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-aarch_64.zip"}
+
-"platforms.linux-x64" = { checksum = "sha256:48785a926e73ffa3f68e2f22b14e7b849620c7a1d36809ac9249a5495e280323", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-x86_64.zip"}
+[tools.protoc."platforms.linux-arm64"]
-"platforms.macos-arm64" = { checksum = "sha256:b9576b5fa1a1ef3fe13a8c91d9d8204b46545759bea5ae155cd6ba2ea4cdaeed", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-osx-aarch_64.zip"}
+checksum = "sha256:2594ff4fcae8cb57310d394d0961b236190ad9c5efbfdf1f597ea471d424fe79"
-"platforms.macos-x64" = { checksum = "sha256:312f04713946921cc0187ef34df80241ddca1bab6f564c636885fd2cc90d3f88", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-osx-x86_64.zip"}
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-aarch_64.zip"
-"platforms.windows-x64" = { checksum = "sha256:1ebd7c87baffb9f1c47169b640872bf5fb1e4408079c691af527be9561d8f6f7", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-win64.zip"}
+
+[tools.protoc."platforms.linux-arm64-musl"]
+checksum = "sha256:2594ff4fcae8cb57310d394d0961b236190ad9c5efbfdf1f597ea471d424fe79"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-aarch_64.zip"
+
+[tools.protoc."platforms.linux-x64"]
+checksum = "sha256:48785a926e73ffa3f68e2f22b14e7b849620c7a1d36809ac9249a5495e280323"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-x86_64.zip"
+
+[tools.protoc."platforms.linux-x64-musl"]
+checksum = "sha256:48785a926e73ffa3f68e2f22b14e7b849620c7a1d36809ac9249a5495e280323"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-linux-x86_64.zip"
+
+[tools.protoc."platforms.macos-arm64"]
+checksum = "sha256:b9576b5fa1a1ef3fe13a8c91d9d8204b46545759bea5ae155cd6ba2ea4cdaeed"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-osx-aarch_64.zip"
+
+[tools.protoc."platforms.macos-x64"]
+checksum = "sha256:312f04713946921cc0187ef34df80241ddca1bab6f564c636885fd2cc90d3f88"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-osx-x86_64.zip"
+
+[tools.protoc."platforms.windows-x64"]
+checksum = "sha256:1ebd7c87baffb9f1c47169b640872bf5fb1e4408079c691af527be9561d8f6f7"
+url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-win64.zip"
 
 [[tools.python]]
 version = "3.14.3"
 backend = "core:python"
-"platforms.linux-arm64" = { checksum = "sha256:be0f4dc2932f762292b27d46ea7d3e8e66ddf3969a5eb0254a229015ed402625", url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260303/cpython-3.14.3+20260303-aarch64-unknown-linux-gnu-install_only_stripped.tar.gz"}
+
-"platforms.linux-x64" = { checksum = "sha256:0a73413f89efd417871876c9accaab28a9d1e3cd6358fbfff171a38ec99302f0", url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260303/cpython-3.14.3+20260303-x86_64-unknown-linux-gnu-install_only_stripped.tar.gz"}
+[tools.python."platforms.linux-arm64"]
-"platforms.macos-arm64" = { checksum = "sha256:4703cdf18b26798fde7b49b6b66149674c25f97127be6a10dbcf29309bdcdcdb", url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260303/cpython-3.14.3+20260303-aarch64-apple-darwin-install_only_stripped.tar.gz"}
+checksum = "sha256:53700338695e402a1a1fe22be4a41fbdacc70e22bb308a48eca8ed67cb7992be"
-"platforms.macos-x64" = { checksum = "sha256:76f1cc26e3d262eae8ca546a93e8bded10cf0323613f7e246fea2e10a8115eb7", url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260303/cpython-3.14.3+20260303-x86_64-apple-darwin-install_only_stripped.tar.gz"}
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-aarch64-unknown-linux-gnu-install_only_stripped.tar.gz"
-"platforms.windows-x64" = { checksum = "sha256:950c5f21a015c1bdd1337f233456df2470fab71e4d794407d27a84cb8b9909a0", url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260303/cpython-3.14.3+20260303-x86_64-pc-windows-msvc-install_only_stripped.tar.gz"}
+
+[tools.python."platforms.linux-arm64-musl"]
+checksum = "sha256:53700338695e402a1a1fe22be4a41fbdacc70e22bb308a48eca8ed67cb7992be"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-aarch64-unknown-linux-gnu-install_only_stripped.tar.gz"
+
+[tools.python."platforms.linux-x64"]
+checksum = "sha256:d7a9f970914bb4c88756fe3bdcc186d4feb90e9500e54f1db47dae4dc9687e39"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-unknown-linux-gnu-install_only_stripped.tar.gz"
+
+[tools.python."platforms.linux-x64-musl"]
+checksum = "sha256:d7a9f970914bb4c88756fe3bdcc186d4feb90e9500e54f1db47dae4dc9687e39"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-unknown-linux-gnu-install_only_stripped.tar.gz"
+
+[tools.python."platforms.macos-arm64"]
+checksum = "sha256:c43aecde4a663aebff99b9b83da0efec506479f1c3f98331442f33d2c43501f9"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-aarch64-apple-darwin-install_only_stripped.tar.gz"
+
+[tools.python."platforms.macos-x64"]
+checksum = "sha256:9ab41dbc2f100a2a45d1833b9c11165f51051c558b5213eda9a9731d5948a0c0"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-apple-darwin-install_only_stripped.tar.gz"
+
+[tools.python."platforms.windows-x64"]
+checksum = "sha256:bbe19034b35b0267176a7442575ae7dc6343480fd4d35598cb7700173d431e09"
+url = "https://github.com/astral-sh/python-build-standalone/releases/download/20260324/cpython-3.14.3+20260324-x86_64-pc-windows-msvc-install_only_stripped.tar.gz"
 
 [[tools.rust]]
 version = "1.93.0"

mise.toml

@@ -10,3 +10,13 @@ protoc = "29.6"
 "cargo:cargo-shear" = "latest"
 "cargo:cargo-insta" = "1.46.3"
 python = "3.14.3"
+ast-grep = "0.42.0"
+"cargo:cargo-edit" = "0.13.9"
+
+[tasks.codegen]
+sources = ['protobufs/*.proto', 'protobufs/**/*.proto']
+outputs = ['useragent/lib/proto/**']
+run = '''
+dart pub global activate protoc_plugin && \
+protoc --dart_out=grpc:useragent/lib/proto --proto_path=protobufs/ $(find protobufs -name '*.proto' | sort)
+'''

protobufs/client.proto

@@ -2,46 +2,24 @@ syntax = "proto3";
 
 package arbiter.client;
 
-import "evm.proto";
+import "client/auth.proto";
-
+import "client/evm.proto";
-message AuthChallengeRequest {
+import "client/vault.proto";
-  bytes pubkey = 1;
-}
-
-message AuthChallenge {
-  bytes pubkey = 1;
-  int32 nonce = 2;
-}
-
-message AuthChallengeSolution {
-  bytes signature = 1;
-}
-
-message AuthOk {}
 
 message ClientRequest {
+  int32 request_id = 4;
   oneof payload {
-    AuthChallengeRequest auth_challenge_request = 1;
+    auth.Request auth = 1;
-    AuthChallengeSolution auth_challenge_solution = 2;
+    vault.Request vault = 2;
-    arbiter.evm.EvmSignTransactionRequest evm_sign_transaction = 3;
+    evm.Request evm = 3;
   }
 }
 
-message ClientConnectError {
-  enum Code {
-    UNKNOWN = 0;
-    APPROVAL_DENIED = 1;
-    NO_USER_AGENTS_ONLINE = 2;
-  }
-  Code code = 1;
-}
-
 message ClientResponse {
+  optional int32 request_id = 7;
   oneof payload {
-    AuthChallenge auth_challenge = 1;
+    auth.Response auth = 1;
-    AuthOk auth_ok = 2;
+    vault.Response vault = 2;
-    ClientConnectError client_connect_error = 5;
+    evm.Response evm = 3;
-    arbiter.evm.EvmSignTransactionResponse evm_sign_transaction = 3;
-    arbiter.evm.EvmAnalyzeTransactionResponse evm_analyze_transaction = 4;
   }
 }

protobufs/client/auth.proto

@@ -0,0 +1,43 @@
+syntax = "proto3";
+
+package arbiter.client.auth;
+
+import "shared/client.proto";
+
+message AuthChallengeRequest {
+  bytes pubkey = 1;
+  arbiter.shared.ClientInfo client_info = 2;
+}
+
+message AuthChallenge {
+  bytes pubkey = 1;
+  int32 nonce = 2;
+}
+
+message AuthChallengeSolution {
+  bytes signature = 1;
+}
+
+enum AuthResult {
+  AUTH_RESULT_UNSPECIFIED = 0;
+  AUTH_RESULT_SUCCESS = 1;
+  AUTH_RESULT_INVALID_KEY = 2;
+  AUTH_RESULT_INVALID_SIGNATURE = 3;
+  AUTH_RESULT_APPROVAL_DENIED = 4;
+  AUTH_RESULT_NO_USER_AGENTS_ONLINE = 5;
+  AUTH_RESULT_INTERNAL = 6;
+}
+
+message Request {
+  oneof payload {
+    AuthChallengeRequest challenge_request = 1;
+    AuthChallengeSolution challenge_solution = 2;
+  }
+}
+
+message Response {
+  oneof payload {
+    AuthChallenge challenge = 1;
+    AuthResult result = 2;
+  }
+}

protobufs/client/evm.proto

@@ -0,0 +1,19 @@
+syntax = "proto3";
+
+package arbiter.client.evm;
+
+import "evm.proto";
+
+message Request {
+  oneof payload {
+    arbiter.evm.EvmSignTransactionRequest sign_transaction = 1;
+    arbiter.evm.EvmAnalyzeTransactionRequest analyze_transaction = 2;
+  }
+}
+
+message Response {
+  oneof payload {
+    arbiter.evm.EvmSignTransactionResponse sign_transaction = 1;
+    arbiter.evm.EvmAnalyzeTransactionResponse analyze_transaction = 2;
+  }
+}

protobufs/client/vault.proto

@@ -0,0 +1,18 @@
+syntax = "proto3";
+
+package arbiter.client.vault;
+
+import "google/protobuf/empty.proto";
+import "shared/vault.proto";
+
+message Request {
+  oneof payload {
+    google.protobuf.Empty query_state = 1;
+  }
+}
+
+message Response {
+  oneof payload {
+    arbiter.shared.VaultState state = 1;
+  }
+}

protobufs/evm.proto

@@ -4,6 +4,7 @@ package arbiter.evm;
 
 import "google/protobuf/empty.proto";
 import "google/protobuf/timestamp.proto";
+import "shared/evm.proto";
 
 enum EvmError {
   EVM_ERROR_UNSPECIFIED = 0;
@@ -12,7 +13,8 @@ enum EvmError {
 }
 
 message WalletEntry {
-  bytes address = 1; // 20-byte Ethereum address
+  int32 id = 1;
+  bytes address = 2; // 20-byte Ethereum address
 }
 
 message WalletList {
@@ -46,7 +48,7 @@ message VolumeRateLimit {
 }
 
 message SharedSettings {
-  int32 wallet_id = 1;
+  int32 wallet_access_id = 1;
   uint64 chain_id = 2;
   optional google.protobuf.Timestamp valid_from = 3;
   optional google.protobuf.Timestamp valid_until = 4;
@@ -73,75 +75,10 @@ message SpecificGrant {
   }
 }
 
-message EtherTransferMeaning {
-  bytes to = 1; // 20-byte Ethereum address
-  bytes value = 2; // U256 as big-endian bytes
-}
-
-message TokenInfo {
-  string symbol = 1;
-  bytes address = 2; // 20-byte Ethereum address
-  uint64 chain_id = 3;
-}
-
-// Mirror of token_transfers::Meaning
-message TokenTransferMeaning {
-  TokenInfo token = 1;
-  bytes to = 2; // 20-byte Ethereum address
-  bytes value = 3; // U256 as big-endian bytes
-}
-
-// Mirror of policies::SpecificMeaning
-message SpecificMeaning {
-  oneof meaning {
-    EtherTransferMeaning ether_transfer = 1;
-    TokenTransferMeaning token_transfer = 2;
-  }
-}
-
-// --- Eval error types ---
-message GasLimitExceededViolation {
-  optional bytes max_gas_fee_per_gas = 1; // U256 as big-endian bytes
-  optional bytes max_priority_fee_per_gas = 2; // U256 as big-endian bytes
-}
-
-message EvalViolation {
-  oneof kind {
-    bytes invalid_target = 1; // 20-byte Ethereum address
-    GasLimitExceededViolation gas_limit_exceeded = 2;
-    google.protobuf.Empty rate_limit_exceeded = 3;
-    google.protobuf.Empty volumetric_limit_exceeded = 4;
-    google.protobuf.Empty invalid_time = 5;
-    google.protobuf.Empty invalid_transaction_type = 6;
-  }
-}
-
-// Transaction was classified but no grant covers it
-message NoMatchingGrantError {
-  SpecificMeaning meaning = 1;
-}
-
-// Transaction was classified and a grant was found, but constraints were violated
-message PolicyViolationsError {
-  SpecificMeaning meaning = 1;
-  repeated EvalViolation violations = 2;
-}
-
-// top-level error returned when transaction evaluation fails
-message TransactionEvalError {
-  oneof kind {
-    google.protobuf.Empty contract_creation_not_supported = 1;
-    google.protobuf.Empty unsupported_transaction_type = 2;
-    NoMatchingGrantError no_matching_grant = 3;
-    PolicyViolationsError policy_violations = 4;
-  }
-}
-
 // --- UserAgent grant management ---
 message EvmGrantCreateRequest {
-  int32 client_id = 1;
+  SharedSettings shared = 1;
-  SharedSettings shared = 2;
+  SpecificGrant specific = 2;
-  SpecificGrant specific = 3;
 }
 
 message EvmGrantCreateResponse {
@@ -165,13 +102,13 @@ message EvmGrantDeleteResponse {
 // Basic grant info returned in grant listings
 message GrantEntry {
   int32 id = 1;
-  int32 client_id = 2;
+  int32 wallet_access_id = 2;
   SharedSettings shared = 3;
   SpecificGrant specific = 4;
 }
 
 message EvmGrantListRequest {
-  optional int32 wallet_id = 1;
+  optional int32 wallet_access_id = 1;
 }
 
 message EvmGrantListResponse {
@@ -197,7 +134,7 @@ message EvmSignTransactionRequest {
 message EvmSignTransactionResponse {
   oneof result {
     bytes signature = 1; // 65-byte signature: r[32] || s[32] || v[1]
-    TransactionEvalError eval_error = 2;
+    arbiter.shared.evm.TransactionEvalError eval_error = 2;
     EvmError error = 3;
   }
 }
@@ -209,8 +146,8 @@ message EvmAnalyzeTransactionRequest {
 
 message EvmAnalyzeTransactionResponse {
   oneof result {
-    SpecificMeaning meaning = 1;
+    arbiter.shared.evm.SpecificMeaning meaning = 1;
-    TransactionEvalError eval_error = 2;
+    arbiter.shared.evm.TransactionEvalError eval_error = 2;
     EvmError error = 3;
   }
 }

protobufs/shared/client.proto

@@ -0,0 +1,9 @@
+syntax = "proto3";
+
+package arbiter.shared;
+
+message ClientInfo {
+  string name = 1;
+  optional string description = 2;
+  optional string version = 3;
+}

protobufs/shared/evm.proto

@@ -0,0 +1,68 @@
+syntax = "proto3";
+
+package arbiter.shared.evm;
+
+import "google/protobuf/empty.proto";
+
+message EtherTransferMeaning {
+  bytes to = 1; // 20-byte Ethereum address
+  bytes value = 2; // U256 as big-endian bytes
+}
+
+message TokenInfo {
+  string symbol = 1;
+  bytes address = 2; // 20-byte Ethereum address
+  uint64 chain_id = 3;
+}
+
+// Mirror of token_transfers::Meaning
+message TokenTransferMeaning {
+  TokenInfo token = 1;
+  bytes to = 2; // 20-byte Ethereum address
+  bytes value = 3; // U256 as big-endian bytes
+}
+
+// Mirror of policies::SpecificMeaning
+message SpecificMeaning {
+  oneof meaning {
+    EtherTransferMeaning ether_transfer = 1;
+    TokenTransferMeaning token_transfer = 2;
+  }
+}
+
+message GasLimitExceededViolation {
+  optional bytes max_gas_fee_per_gas = 1; // U256 as big-endian bytes
+  optional bytes max_priority_fee_per_gas = 2; // U256 as big-endian bytes
+}
+
+message EvalViolation {
+  oneof kind {
+    bytes invalid_target = 1; // 20-byte Ethereum address
+    GasLimitExceededViolation gas_limit_exceeded = 2;
+    google.protobuf.Empty rate_limit_exceeded = 3;
+    google.protobuf.Empty volumetric_limit_exceeded = 4;
+    google.protobuf.Empty invalid_time = 5;
+    google.protobuf.Empty invalid_transaction_type = 6;
+  }
+}
+
+// Transaction was classified but no grant covers it
+message NoMatchingGrantError {
+  SpecificMeaning meaning = 1;
+}
+
+// Transaction was classified and a grant was found, but constraints were violated
+message PolicyViolationsError {
+  SpecificMeaning meaning = 1;
+  repeated EvalViolation violations = 2;
+}
+
+// top-level error returned when transaction evaluation fails
+message TransactionEvalError {
+  oneof kind {
+    google.protobuf.Empty contract_creation_not_supported = 1;
+    google.protobuf.Empty unsupported_transaction_type = 2;
+    NoMatchingGrantError no_matching_grant = 3;
+    PolicyViolationsError policy_violations = 4;
+  }
+}

protobufs/shared/vault.proto

@@ -0,0 +1,11 @@
+syntax = "proto3";
+
+package arbiter.shared;
+
+enum VaultState {
+  VAULT_STATE_UNSPECIFIED = 0;
+  VAULT_STATE_UNBOOTSTRAPPED = 1;
+  VAULT_STATE_SEALED = 2;
+  VAULT_STATE_UNSEALED = 3;
+  VAULT_STATE_ERROR = 4;
+}

protobufs/user_agent.proto

@@ -2,143 +2,27 @@ syntax = "proto3";
 
 package arbiter.user_agent;
 
-import "google/protobuf/empty.proto";
+import "user_agent/auth.proto";
-import "evm.proto";
+import "user_agent/evm.proto";
-
+import "user_agent/sdk_client.proto";
-enum KeyType {
+import "user_agent/vault/vault.proto";
-  KEY_TYPE_UNSPECIFIED = 0;
-  KEY_TYPE_ED25519 = 1;
-  KEY_TYPE_ECDSA_SECP256K1 = 2;
-  KEY_TYPE_RSA = 3;
-}
-
-// --- SDK client management ---
-
-enum SdkClientError {
-  SDK_CLIENT_ERROR_UNSPECIFIED = 0;
-  SDK_CLIENT_ERROR_ALREADY_EXISTS = 1;
-  SDK_CLIENT_ERROR_NOT_FOUND = 2;
-  SDK_CLIENT_ERROR_HAS_RELATED_DATA = 3; // hard-delete blocked by FK (client has grants or transaction logs)
-  SDK_CLIENT_ERROR_INTERNAL = 4;
-}
-
-message SdkClientApproveRequest {
-  bytes pubkey = 1; // 32-byte ed25519 public key
-}
-
-message SdkClientRevokeRequest {
-  int32 client_id = 1;
-}
-
-message SdkClientEntry {
-  int32 id = 1;
-  bytes pubkey = 2;
-  int32 created_at = 3;
-}
-
-message SdkClientList {
-  repeated SdkClientEntry clients = 1;
-}
-
-message SdkClientApproveResponse {
-  oneof result {
-    SdkClientEntry client = 1;
-    SdkClientError error = 2;
-  }
-}
-
-message SdkClientRevokeResponse {
-  oneof result {
-    google.protobuf.Empty ok = 1;
-    SdkClientError error = 2;
-  }
-}
-
-message SdkClientListResponse {
-  oneof result {
-    SdkClientList clients = 1;
-    SdkClientError error = 2;
-  }
-}
-
-message AuthChallengeRequest {
-  bytes pubkey = 1;
-  optional string bootstrap_token = 2;
-  KeyType key_type = 3;
-}
-
-message AuthChallenge {
-  bytes pubkey = 1;
-  int32 nonce = 2;
-}
-
-message AuthChallengeSolution {
-  bytes signature = 1;
-}
-
-message AuthOk {}
-
-message UnsealStart {
-  bytes client_pubkey = 1;
-}
-
-message UnsealStartResponse {
-  bytes server_pubkey = 1;
-}
-message UnsealEncryptedKey {
-  bytes nonce = 1;
-  bytes ciphertext = 2;
-  bytes associated_data = 3;
-}
-
-enum UnsealResult {
-  UNSEAL_RESULT_UNSPECIFIED = 0;
-  UNSEAL_RESULT_SUCCESS = 1;
-  UNSEAL_RESULT_INVALID_KEY = 2;
-  UNSEAL_RESULT_UNBOOTSTRAPPED = 3;
-}
-
-enum VaultState {
-  VAULT_STATE_UNSPECIFIED = 0;
-  VAULT_STATE_UNBOOTSTRAPPED = 1;
-  VAULT_STATE_SEALED = 2;
-  VAULT_STATE_UNSEALED = 3;
-  VAULT_STATE_ERROR = 4;
-}
 
 message UserAgentRequest {
+  int32 id = 16;
   oneof payload {
-    AuthChallengeRequest auth_challenge_request = 1;
+    auth.Request auth = 1;
-    AuthChallengeSolution auth_challenge_solution = 2;
+    vault.Request vault = 2;
-    UnsealStart unseal_start = 3;
+    evm.Request evm = 3;
-    UnsealEncryptedKey unseal_encrypted_key = 4;
+    sdk_client.Request sdk_client = 4;
-    google.protobuf.Empty query_vault_state = 5;
-    google.protobuf.Empty evm_wallet_create = 6;
-    google.protobuf.Empty evm_wallet_list = 7;
-    arbiter.evm.EvmGrantCreateRequest evm_grant_create = 8;
-    arbiter.evm.EvmGrantDeleteRequest evm_grant_delete = 9;
-    arbiter.evm.EvmGrantListRequest evm_grant_list = 10;
-    // field 11 reserved: was client_connection_response (online approval removed)
-    SdkClientApproveRequest sdk_client_approve = 12;
-    SdkClientRevokeRequest sdk_client_revoke = 13;
-    google.protobuf.Empty sdk_client_list = 14;
   }
 }
+
 message UserAgentResponse {
+  optional int32 id = 16;
   oneof payload {
-    AuthChallenge auth_challenge = 1;
+    auth.Response auth = 1;
-    AuthOk auth_ok = 2;
+    vault.Response vault = 2;
-    UnsealStartResponse unseal_start_response = 3;
+    evm.Response evm = 3;
-    UnsealResult unseal_result = 4;
+    sdk_client.Response sdk_client = 4;
-    VaultState vault_state = 5;
-    arbiter.evm.WalletCreateResponse evm_wallet_create = 6;
-    arbiter.evm.WalletListResponse evm_wallet_list = 7;
-    arbiter.evm.EvmGrantCreateResponse evm_grant_create = 8;
-    arbiter.evm.EvmGrantDeleteResponse evm_grant_delete = 9;
-    arbiter.evm.EvmGrantListResponse evm_grant_list = 10;
-    // fields 11, 12 reserved: were client_connection_request, client_connection_cancel (online approval removed)
-    SdkClientApproveResponse sdk_client_approve = 13;
-    SdkClientRevokeResponse sdk_client_revoke = 14;
-    SdkClientListResponse sdk_client_list = 15;
   }
 }

protobufs/user_agent/auth.proto

@@ -0,0 +1,48 @@
+syntax = "proto3";
+
+package arbiter.user_agent.auth;
+
+enum KeyType {
+  KEY_TYPE_UNSPECIFIED = 0;
+  KEY_TYPE_ED25519 = 1;
+  KEY_TYPE_ECDSA_SECP256K1 = 2;
+  KEY_TYPE_RSA = 3;
+}
+
+message AuthChallengeRequest {
+  bytes pubkey = 1;
+  optional string bootstrap_token = 2;
+  KeyType key_type = 3;
+}
+
+message AuthChallenge {
+  int32 nonce = 1;
+}
+
+message AuthChallengeSolution {
+  bytes signature = 1;
+}
+
+enum AuthResult {
+  AUTH_RESULT_UNSPECIFIED = 0;
+  AUTH_RESULT_SUCCESS = 1;
+  AUTH_RESULT_INVALID_KEY = 2;
+  AUTH_RESULT_INVALID_SIGNATURE = 3;
+  AUTH_RESULT_BOOTSTRAP_REQUIRED = 4;
+  AUTH_RESULT_TOKEN_INVALID = 5;
+  AUTH_RESULT_INTERNAL = 6;
+}
+
+message Request {
+  oneof payload {
+    AuthChallengeRequest challenge_request = 1;
+    AuthChallengeSolution challenge_solution = 2;
+  }
+}
+
+message Response {
+  oneof payload {
+    AuthChallenge challenge = 1;
+    AuthResult result = 2;
+  }
+}

protobufs/user_agent/evm.proto

@@ -0,0 +1,33 @@
+syntax = "proto3";
+
+package arbiter.user_agent.evm;
+
+import "evm.proto";
+import "google/protobuf/empty.proto";
+
+message SignTransactionRequest {
+  int32 client_id = 1;
+  arbiter.evm.EvmSignTransactionRequest request = 2;
+}
+
+message Request {
+  oneof payload {
+    google.protobuf.Empty wallet_create = 1;
+    google.protobuf.Empty wallet_list = 2;
+    arbiter.evm.EvmGrantCreateRequest grant_create = 3;
+    arbiter.evm.EvmGrantDeleteRequest grant_delete = 4;
+    arbiter.evm.EvmGrantListRequest grant_list = 5;
+    SignTransactionRequest sign_transaction = 6;
+  }
+}
+
+message Response {
+  oneof payload {
+    arbiter.evm.WalletCreateResponse wallet_create = 1;
+    arbiter.evm.WalletListResponse wallet_list = 2;
+    arbiter.evm.EvmGrantCreateResponse grant_create = 3;
+    arbiter.evm.EvmGrantDeleteResponse grant_delete = 4;
+    arbiter.evm.EvmGrantListResponse grant_list = 5;
+    arbiter.evm.EvmSignTransactionResponse sign_transaction = 6;
+  }
+}

protobufs/user_agent/sdk_client.proto

@@ -0,0 +1,100 @@
+syntax = "proto3";
+
+package arbiter.user_agent.sdk_client;
+
+import "shared/client.proto";
+import "google/protobuf/empty.proto";
+
+enum Error {
+  ERROR_UNSPECIFIED = 0;
+  ERROR_ALREADY_EXISTS = 1;
+  ERROR_NOT_FOUND = 2;
+  ERROR_HAS_RELATED_DATA = 3; // hard-delete blocked by FK (client has grants or transaction logs)
+  ERROR_INTERNAL = 4;
+}
+
+message RevokeRequest {
+  int32 client_id = 1;
+}
+
+message Entry {
+  int32 id = 1;
+  bytes pubkey = 2;
+  arbiter.shared.ClientInfo info = 3;
+  int32 created_at = 4;
+}
+
+message List {
+  repeated Entry clients = 1;
+}
+
+message RevokeResponse {
+  oneof result {
+    google.protobuf.Empty ok = 1;
+    Error error = 2;
+  }
+}
+
+message ListResponse {
+  oneof result {
+    List clients = 1;
+    Error error = 2;
+  }
+}
+
+message ConnectionRequest {
+  bytes pubkey = 1;
+  arbiter.shared.ClientInfo info = 2;
+}
+
+message ConnectionResponse {
+  bool approved = 1;
+  bytes pubkey = 2;
+}
+
+message ConnectionCancel {
+  bytes pubkey = 1;
+}
+
+message WalletAccess {
+  int32 wallet_id = 1;
+  int32 sdk_client_id = 2;
+}
+
+message WalletAccessEntry {
+  int32 id = 1;
+  WalletAccess access = 2;
+}
+
+message GrantWalletAccess {
+  repeated WalletAccess accesses = 1;
+}
+
+message RevokeWalletAccess {
+  repeated int32 accesses = 1;
+}
+
+message ListWalletAccessResponse {
+  repeated WalletAccessEntry accesses = 1;
+}
+
+message Request {
+  oneof payload {
+    ConnectionResponse connection_response = 1;
+    RevokeRequest revoke = 2;
+    google.protobuf.Empty list = 3;
+    GrantWalletAccess grant_wallet_access = 4;
+    RevokeWalletAccess revoke_wallet_access = 5;
+    google.protobuf.Empty list_wallet_access = 6;
+  }
+}
+
+message Response {
+  oneof payload {
+    ConnectionRequest connection_request = 1;
+    ConnectionCancel connection_cancel = 2;
+    RevokeResponse revoke = 3;
+    ListResponse list = 4;
+    ListWalletAccessResponse list_wallet_access = 5;
+  }
+}

protobufs/user_agent/vault/bootstrap.proto

@@ -0,0 +1,24 @@
+syntax = "proto3";
+
+package arbiter.user_agent.vault.bootstrap;
+
+message BootstrapEncryptedKey {
+  bytes nonce = 1;
+  bytes ciphertext = 2;
+  bytes associated_data = 3;
+}
+
+enum BootstrapResult {
+  BOOTSTRAP_RESULT_UNSPECIFIED = 0;
+  BOOTSTRAP_RESULT_SUCCESS = 1;
+  BOOTSTRAP_RESULT_ALREADY_BOOTSTRAPPED = 2;
+  BOOTSTRAP_RESULT_INVALID_KEY = 3;
+}
+
+message Request {
+  BootstrapEncryptedKey encrypted_key = 2;
+}
+
+message Response {
+  BootstrapResult result = 1;
+}

protobufs/user_agent/vault/unseal.proto

@@ -0,0 +1,37 @@
+syntax = "proto3";
+
+package arbiter.user_agent.vault.unseal;
+
+message UnsealStart {
+  bytes client_pubkey = 1;
+}
+
+message UnsealStartResponse {
+  bytes server_pubkey = 1;
+}
+message UnsealEncryptedKey {
+  bytes nonce = 1;
+  bytes ciphertext = 2;
+  bytes associated_data = 3;
+}
+
+enum UnsealResult {
+  UNSEAL_RESULT_UNSPECIFIED = 0;
+  UNSEAL_RESULT_SUCCESS = 1;
+  UNSEAL_RESULT_INVALID_KEY = 2;
+  UNSEAL_RESULT_UNBOOTSTRAPPED = 3;
+}
+
+message Request {
+  oneof payload {
+    UnsealStart start = 1;
+    UnsealEncryptedKey encrypted_key = 2;
+  }
+}
+
+message Response {
+  oneof payload {
+    UnsealStartResponse start = 1;
+    UnsealResult result = 2;
+  }
+}

protobufs/user_agent/vault/vault.proto

@@ -0,0 +1,24 @@
+syntax = "proto3";
+
+package arbiter.user_agent.vault;
+
+import "google/protobuf/empty.proto";
+import "shared/vault.proto";
+import "user_agent/vault/bootstrap.proto";
+import "user_agent/vault/unseal.proto";
+
+message Request {
+  oneof payload {
+    google.protobuf.Empty query_state = 1;
+    unseal.Request unseal = 2;
+    bootstrap.Request bootstrap = 3;
+  }
+}
+
+message Response {
+  oneof payload {
+    arbiter.shared.VaultState state = 1;
+    unseal.Response unseal = 2;
+    bootstrap.Response bootstrap = 3;
+  }
+}

server/Cargo.lock

@@ -67,13 +67,13 @@ dependencies = [
 
 [[package]]
 name = "alloy-chains"
-version = "0.2.31"
+version = "0.2.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6d9d22005bf31b018f31ef9ecadb5d2c39cf4f6acc8db0456f72c815f3d7f757"
+checksum = "9247f0a399ef71aeb68f497b2b8fb348014f742b50d3b83b1e00dfe1b7d64b3d"
 dependencies = [
  "alloy-primitives",
  "num_enum",
- "strum",
+ "strum 0.27.2",
 ]
 
 [[package]]
@@ -100,7 +100,7 @@ dependencies = [
  "serde",
  "serde_json",
  "serde_with",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -136,7 +136,7 @@ dependencies = [
  "futures",
  "futures-util",
  "serde_json",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -165,7 +165,7 @@ dependencies = [
  "itoa",
  "serde",
  "serde_json",
- "winnow",
+ "winnow 0.7.15",
 ]
 
 [[package]]
@@ -178,7 +178,7 @@ dependencies = [
  "alloy-rlp",
  "crc",
  "serde",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -203,7 +203,7 @@ dependencies = [
  "alloy-rlp",
  "borsh",
  "serde",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -239,7 +239,7 @@ dependencies = [
  "serde",
  "serde_with",
  "sha2 0.10.9",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -280,7 +280,7 @@ dependencies = [
  "http",
  "serde",
  "serde_json",
- "thiserror",
+ "thiserror 2.0.18",
  "tracing",
 ]
 
@@ -307,7 +307,7 @@ dependencies = [
  "futures-utils-wasm",
  "serde",
  "serde_json",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -382,7 +382,7 @@ dependencies = [
  "reqwest",
  "serde",
  "serde_json",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
  "tracing",
  "url",
@@ -471,11 +471,11 @@ dependencies = [
  "alloy-rlp",
  "alloy-serde",
  "alloy-sol-types",
- "itertools 0.14.0",
+ "itertools 0.13.0",
  "serde",
  "serde_json",
  "serde_with",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -501,7 +501,7 @@ dependencies = [
  "either",
  "elliptic-curve",
  "k256",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -517,7 +517,7 @@ dependencies = [
  "async-trait",
  "k256",
  "rand 0.8.5",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -578,7 +578,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a6df77fea9d6a2a75c0ef8d2acbdfd92286cc599983d3175ccdc170d3433d249"
 dependencies = [
  "serde",
- "winnow",
+ "winnow 0.7.15",
 ]
 
 [[package]]
@@ -608,7 +608,7 @@ dependencies = [
  "parking_lot",
  "serde",
  "serde_json",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
  "tower",
  "tracing",
@@ -624,7 +624,7 @@ checksum = "aa501ad58dd20acddbfebc65b52e60f05ebf97c52fa40d1b35e91f5e2da0ad0e"
 dependencies = [
  "alloy-json-rpc",
  "alloy-transport",
- "itertools 0.14.0",
+ "itertools 0.13.0",
  "reqwest",
  "serde_json",
  "tower",
@@ -644,7 +644,7 @@ dependencies = [
  "nybbles",
  "serde",
  "smallvec",
- "thiserror",
+ "thiserror 2.0.18",
  "tracing",
 ]
 
@@ -684,8 +684,9 @@ dependencies = [
  "async-trait",
  "ed25519-dalek",
  "http",
+ "rand 0.10.0",
  "rustls-webpki",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
  "tokio-stream",
  "tonic",
@@ -708,8 +709,9 @@ dependencies = [
  "rcgen",
  "rstest",
  "rustls-pki-types",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
+ "tokio-stream",
  "tonic",
  "tonic-prost",
  "tonic-prost-build",
@@ -722,6 +724,7 @@ name = "arbiter-server"
 version = "0.1.0"
 dependencies = [
  "alloy",
+ "anyhow",
  "arbiter-proto",
  "arbiter-tokens-registry",
  "argon2",
@@ -733,13 +736,15 @@ dependencies = [
  "diesel-async",
  "diesel_migrations",
  "ed25519-dalek",
+ "fatality",
  "futures",
+ "hmac",
  "insta",
  "k256",
  "kameo",
  "memsafe",
- "miette",
  "pem",
+ "prost-types",
  "rand 0.10.0",
  "rcgen",
  "restructed",
@@ -749,9 +754,9 @@ dependencies = [
  "sha2 0.10.9",
  "smlang",
  "spki",
- "strum",
+ "strum 0.28.0",
  "test-log",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
  "tokio-stream",
  "tonic",
@@ -761,13 +766,6 @@ dependencies = [
  "zeroize",
 ]
 
-[[package]]
-name = "arbiter-terrors-poc"
-version = "0.1.0"
-dependencies = [
- "terrors",
-]
-
 [[package]]
 name = "arbiter-tokens-registry"
 version = "0.1.0"
@@ -775,30 +773,6 @@ dependencies = [
  "alloy",
 ]
 
-[[package]]
-name = "arbiter-useragent"
-version = "0.1.0"
-dependencies = [
- "arbiter-proto",
- "async-trait",
- "ed25519-dalek",
- "http",
- "k256",
- "kameo",
- "rand 0.10.0",
- "rsa",
- "rustls-webpki",
- "sha2 0.10.9",
- "smlang",
- "spki",
- "thiserror",
- "tokio",
- "tokio-stream",
- "tonic",
- "tracing",
- "x25519-dalek",
-]
-
 [[package]]
 name = "argon2"
 version = "0.5.3"
@@ -1019,7 +993,7 @@ dependencies = [
  "nom",
  "num-traits",
  "rusticata-macros",
- "thiserror",
+ "thiserror 2.0.18",
  "time",
 ]
 
@@ -1104,9 +1078,9 @@ checksum = "c08606f8c3cbf4ce6ec8e28fb0014a2c086708fe954eaa885384a6165172e7e8"
 
 [[package]]
 name = "aws-lc-rs"
-version = "1.16.1"
+version = "1.16.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "94bffc006df10ac2a68c83692d734a465f8ee6c5b384d8545a636f81d858f4bf"
+checksum = "a054912289d18629dc78375ba2c3726a3afe3ff71b4edba9dedfca0e3446d1fc"
 dependencies = [
  "aws-lc-sys",
  "untrusted 0.7.1",
@@ -1115,9 +1089,9 @@ dependencies = [
 
 [[package]]
 name = "aws-lc-sys"
-version = "0.38.0"
+version = "0.39.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4321e568ed89bb5a7d291a7f37997c2c0df89809d7b6d12062c81ddb54aa782e"
+checksum = "1fa7e52a4c5c547c741610a2c6f123f3881e409b714cd27e6798ef020c514f0a"
 dependencies = [
  "cc",
  "cmake",
@@ -1312,19 +1286,20 @@ dependencies = [
 
 [[package]]
 name = "borsh"
-version = "1.6.0"
+version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d1da5ab77c1437701eeff7c88d968729e7766172279eab0676857b3d63af7a6f"
+checksum = "cfd1e3f8955a5d7de9fab72fc8373fade9fb8a703968cb200ae3dc6cf08e185a"
 dependencies = [
  "borsh-derive",
+ "bytes",
  "cfg_aliases",
 ]
 
 [[package]]
 name = "borsh-derive"
-version = "1.6.0"
+version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0686c856aa6aac0c4498f936d7d6a02df690f614c03e4d906d1018062b5c5e2c"
+checksum = "bfcfdc083699101d5a7965e49925975f2f55060f94f9a05e7187be95d530ca59"
 dependencies = [
  "once_cell",
  "proc-macro-crate",
@@ -1838,15 +1813,16 @@ dependencies = [
 
 [[package]]
 name = "diesel-async"
-version = "0.7.4"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13096fb8dae53f2d411c4b523bec85f45552ed3044a2ab4d85fb2092d9cb4f34"
+checksum = "b95864e58597509106f1fddfe0600de7e589e1fddddd87f54eee0a49fd111bbc"
 dependencies = [
  "bb8",
  "diesel",
  "diesel_migrations",
  "futures-core",
  "futures-util",
+ "pin-project-lite",
  "scoped-futures",
  "tokio",
 ]
@@ -2076,7 +2052,22 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys 0.61.2",
+ "windows-sys 0.52.0",
+]
+
+[[package]]
+name = "expander"
+version = "2.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2c470c71d91ecbd179935b24170459e926382eaaa86b590b78814e180d8a8e2"
+dependencies = [
+ "blake2",
+ "file-guard",
+ "fs-err",
+ "prettyplease",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -2107,6 +2098,30 @@ dependencies = [
  "bytes",
 ]
 
+[[package]]
+name = "fatality"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec6f82451ff7f0568c6181287189126d492b5654e30a788add08027b6363d019"
+dependencies = [
+ "fatality-proc-macro",
+ "thiserror 1.0.69",
+]
+
+[[package]]
+name = "fatality-proc-macro"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eb42427514b063d97ce21d5199f36c0c307d981434a6be32582bc79fe5bd2303"
+dependencies = [
+ "expander",
+ "indexmap 2.13.0",
+ "proc-macro-crate",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.117",
+]
+
 [[package]]
 name = "ff"
 version = "0.13.1"
@@ -2129,6 +2144,16 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "64cd1e32ddd350061ae6edb1b082d7c54915b5c672c389143b9a63403a109f24"
 
+[[package]]
+name = "file-guard"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "21ef72acf95ec3d7dbf61275be556299490a245f017cf084bd23b4f68cf9407c"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "find-msvc-tools"
 version = "0.1.9"
@@ -2190,6 +2215,15 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "fs-err"
+version = "2.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "88a41f105fe1d5b6b34b2055e3dc59bb79b46b48b2040b9e6c7b4b5de097aa41"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "fs_extra"
 version = "1.3.0"
@@ -2838,20 +2872,11 @@ dependencies = [
  "either",
 ]
 
-[[package]]
-name = "itertools"
-version = "0.14.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2b192c782037fadd9cfa75548310488aabdbf3d2da73885b31bd0abd03351285"
-dependencies = [
- "either",
-]
-
 [[package]]
 name = "itoa"
-version = "1.0.17"
+version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "92ecc6618181def0457392ccd0ee51198e065e016d1d527a7ac1b6dc7c1f09d2"
+checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
 
 [[package]]
 name = "jobserver"
@@ -3162,7 +3187,7 @@ version = "0.50.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
 dependencies = [
- "windows-sys 0.61.2",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -3239,9 +3264,9 @@ dependencies = [
 
 [[package]]
 name = "num_enum"
-version = "0.7.5"
+version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b1207a7e20ad57b847bbddc6776b968420d38292bbfe2089accff5e19e82454c"
+checksum = "5d0bca838442ec211fa11de3a8b0e0e8f3a4522575b5c4c06ed722e005036f26"
 dependencies = [
  "num_enum_derive",
  "rustversion",
@@ -3249,9 +3274,9 @@ dependencies = [
 
 [[package]]
 name = "num_enum_derive"
-version = "0.7.5"
+version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ff32365de1b6743cb203b710788263c44a03de03802daf96092f2da4fe6ba4d7"
+checksum = "680998035259dcfcafe653688bf2aa6d3e2dc05e98be6ab46afb089dc84f1df8"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3643,7 +3668,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "343d3bd7056eda839b03204e68deff7d1b13aba7af2b2fd16890697274262ee7"
 dependencies = [
  "heck",
- "itertools 0.14.0",
+ "itertools 0.13.0",
  "log",
  "multimap",
  "petgraph",
@@ -3664,7 +3689,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "27c6023962132f4b30eb4c172c91ce92d933da334c59c23cddee82358ddafb0b"
 dependencies = [
  "anyhow",
- "itertools 0.14.0",
+ "itertools 0.13.0",
  "proc-macro2",
  "quote",
  "syn 2.0.117",
@@ -3746,9 +3771,9 @@ checksum = "95067976aca6421a523e491fce939a3e65249bac4b977adee0ee9771568e8aa3"
 
 [[package]]
 name = "pulldown-cmark"
-version = "0.13.1"
+version = "0.13.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "83c41efbf8f90ac44de7f3a868f0867851d261b56291732d0cbf7cceaaeb55a6"
+checksum = "14104c5a24d9bcf7eb2c24753e0f49fe14555d8bd565ea3d38e4b4303267259d"
 dependencies = [
  "bitflags",
  "memchr",
@@ -3784,7 +3809,7 @@ dependencies = [
  "rustc-hash",
  "rustls",
  "socket2",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
  "tracing",
  "web-time",
@@ -3805,7 +3830,7 @@ dependencies = [
  "rustls",
  "rustls-pki-types",
  "slab",
- "thiserror",
+ "thiserror 2.0.18",
  "tinyvec",
  "tracing",
  "web-time",
@@ -4140,7 +4165,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a8a1f2315036ef6b1fbacd1972e8ee7688030b0a2121edfc2a6550febd41574d"
 dependencies = [
  "hashbrown 0.16.1",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -4261,7 +4286,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys 0.61.2",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]
@@ -4292,9 +4317,9 @@ dependencies = [
 
 [[package]]
 name = "rustls-webpki"
-version = "0.103.9"
+version = "0.103.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d7df23109aa6c1567d1c575b9952556388da57401e4ace1d15f79eedad0d8f53"
+checksum = "df33b2b81ac578cabaf06b89b0631153a3f416b0a886e8a7a1707fb51abbd1ef"
 dependencies = [
  "aws-lc-rs",
  "ring",
@@ -4677,7 +4702,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3a766e1110788c36f4fa1c2b71b387a7815aa65f88ce0229841826633d93723e"
 dependencies = [
  "libc",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -4738,7 +4763,16 @@ version = "0.27.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "af23d6f6c1a224baef9d3f61e287d2761385a5b88fdab4eb4c6f11aeb54c4bcf"
 dependencies = [
- "strum_macros",
+ "strum_macros 0.27.2",
+]
+
+[[package]]
+name = "strum"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9628de9b8791db39ceda2b119bbe13134770b56c138ec1d3af810d045c04f9bd"
+dependencies = [
+ "strum_macros 0.28.0",
 ]
 
 [[package]]
@@ -4753,6 +4787,18 @@ dependencies = [
  "syn 2.0.117",
 ]
 
+[[package]]
+name = "strum_macros"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab85eea0270ee17587ed4156089e10b9e6880ee688791d45a905f5b1ca36f664"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.117",
+]
+
 [[package]]
 name = "subtle"
 version = "2.6.1"
@@ -4850,7 +4896,7 @@ dependencies = [
  "getrandom 0.4.2",
  "once_cell",
  "rustix",
- "windows-sys 0.61.2",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]
@@ -4863,12 +4909,6 @@ dependencies = [
  "windows-sys 0.60.2",
 ]
 
-[[package]]
-name = "terrors"
-version = "0.3.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "987fd8c678ca950df2a18b2c6e9da6ca511d449278fab3565efe0d49c0c07a5d"
-
 [[package]]
 name = "test-log"
 version = "0.2.19"
@@ -4900,13 +4940,33 @@ dependencies = [
  "unicode-width 0.2.2",
 ]
 
+[[package]]
+name = "thiserror"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6aaf5339b578ea85b50e080feb250a3e8ae8cfcdff9a461c9ec2904bc923f52"
+dependencies = [
+ "thiserror-impl 1.0.69",
+]
+
 [[package]]
 name = "thiserror"
 version = "2.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4288b5bcbc7920c07a1149a35cf9590a2aa808e0bc1eafaade0b80947865fbc4"
 dependencies = [
- "thiserror-impl",
+ "thiserror-impl 2.0.18",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fee6c4efc90059e10f81e6d42c60a18f76588c3d74cb83a0b242a2b6c7504c1"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -4981,9 +5041,9 @@ dependencies = [
 
 [[package]]
 name = "tinyvec"
-version = "1.10.0"
+version = "1.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bfa5fdc3bce6191a1dbc8c02d5c8bffcf557bafa17c124c5264a458f1b0613fa"
+checksum = "3e61e67053d25a4e82c844e8424039d9745781b3fc4f32b8d55ed50f5f667ef3"
 dependencies = [
  "tinyvec_macros",
 ]
@@ -5068,7 +5128,7 @@ dependencies = [
  "serde_spanned",
  "toml_datetime 0.7.5+spec-1.1.0",
  "toml_parser",
- "winnow",
+ "winnow 0.7.15",
 ]
 
 [[package]]
@@ -5082,32 +5142,32 @@ dependencies = [
 
 [[package]]
 name = "toml_datetime"
-version = "1.0.0+spec-1.1.0"
+version = "1.0.1+spec-1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "32c2555c699578a4f59f0cc68e5116c8d7cabbd45e1409b989d4be085b53f13e"
+checksum = "9b320e741db58cac564e26c607d3cc1fdc4a88fd36c879568c07856ed83ff3e9"
 dependencies = [
  "serde_core",
 ]
 
 [[package]]
 name = "toml_edit"
-version = "0.25.4+spec-1.1.0"
+version = "0.25.5+spec-1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7193cbd0ce53dc966037f54351dbbcf0d5a642c7f0038c382ef9e677ce8c13f2"
+checksum = "8ca1a40644a28bce036923f6a431df0b34236949d111cc07cb6dca830c9ef2e1"
 dependencies = [
  "indexmap 2.13.0",
- "toml_datetime 1.0.0+spec-1.1.0",
+ "toml_datetime 1.0.1+spec-1.1.0",
  "toml_parser",
- "winnow",
+ "winnow 1.0.0",
 ]
 
 [[package]]
 name = "toml_parser"
-version = "1.0.9+spec-1.1.0"
+version = "1.0.10+spec-1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "702d4415e08923e7e1ef96cd5727c0dfed80b4d2fa25db9647fe5eb6f7c5a4c4"
+checksum = "7df25b4befd31c4816df190124375d5a20c6b6921e2cad937316de3fccd63420"
 dependencies = [
- "winnow",
+ "winnow 1.0.0",
 ]
 
 [[package]]
@@ -5871,6 +5931,15 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "winnow"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a90e88e4667264a994d34e6d1ab2d26d398dcdca8b7f52bec8668957517fc7d8"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "wit-bindgen"
 version = "0.51.0"
@@ -6000,7 +6069,7 @@ dependencies = [
  "nom",
  "oid-registry",
  "rusticata-macros",
- "thiserror",
+ "thiserror 2.0.18",
  "time",
 ]
 
@@ -6038,18 +6107,18 @@ dependencies = [
 
 [[package]]
 name = "zerocopy"
-version = "0.8.42"
+version = "0.8.47"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f2578b716f8a7a858b7f02d5bd870c14bf4ddbbcf3a4c05414ba6503640505e3"
+checksum = "efbb2a062be311f2ba113ce66f697a4dc589f85e78a4aea276200804cea0ed87"
 dependencies = [
  "zerocopy-derive",
 ]
 
 [[package]]
 name = "zerocopy-derive"
-version = "0.8.42"
+version = "0.8.47"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7e6cc098ea4d3bd6246687de65af3f920c430e236bee1e3bf2e441463f08a02f"
+checksum = "0e8bc7269b54418e7aeeef514aa68f8690b8c0489a06b0136e5f57c4c5ccab89"
 dependencies = [
  "proc-macro2",
  "quote",

server/Cargo.toml

@@ -9,23 +9,22 @@ disallowed-methods = "deny"
 
 
 [workspace.dependencies]
-tonic = { version = "0.14.3", features = [
+tonic = { version = "0.14.5", features = [
     "deflate",
     "gzip",
     "tls-connect-info",
     "zstd",
 ] }
 tracing = "0.1.44"
-tokio = { version = "1.49.0", features = ["full"] }
+tokio = { version = "1.50.0", features = ["full"] }
 ed25519-dalek = { version = "3.0.0-pre.6", features = ["rand_core"] }
-chrono = { version = "0.4.43", features = ["serde"] }
+chrono = { version = "0.4.44", features = ["serde"] }
 rand = "0.10.0"
-rustls = "0.23.36"
+rustls = { version = "0.23.37", features = ["aws-lc-rs"] }
 smlang = "0.8.0"
-miette = { version = "7.6.0", features = ["fancy", "serde"] }
 thiserror = "2.0.18"
 async-trait = "0.1.89"
-futures = "0.3.31"
+futures = "0.3.32"
 tokio-stream = { version = "0.1.18", features = ["full"] }
 kameo = "0.19.2"
 prost-types = { version = "0.14.3", features = ["chrono"] }
@@ -43,3 +42,4 @@ k256 = { version = "0.13.4", features = ["ecdsa", "pkcs8"] }
 rsa = { version = "0.9", features = ["sha2"] }
 sha2 = "0.10"
 spki = "0.7"
+miette = { version = "7.6.0", features = ["fancy", "serde"] }

server/crates/arbiter-client/Cargo.toml

@@ -8,9 +8,12 @@ license = "Apache-2.0"
 [lints]
 workspace = true
 
+[features]
+evm = ["dep:alloy"]
+
 [dependencies]
 arbiter-proto.path = "../arbiter-proto"
-alloy.workspace = true
+alloy = { workspace = true, optional = true }
 tonic.workspace = true
 tonic.features = ["tls-aws-lc"]
 tokio.workspace = true
@@ -18,5 +21,6 @@ tokio-stream.workspace = true
 ed25519-dalek.workspace = true
 thiserror.workspace = true
 http = "1.4.0"
-rustls-webpki = { version = "0.103.9", features = ["aws-lc-rs"] }
+rustls-webpki = { version = "0.103.10", features = ["aws-lc-rs"] }
 async-trait.workspace = true
+rand.workspace = true

server/crates/arbiter-client/src/auth.rs

@@ -0,0 +1,149 @@
+use arbiter_proto::{
+    ClientMetadata, format_challenge,
+    proto::{
+        client::{
+            ClientRequest,
+            auth::{
+                self as proto_auth, AuthChallenge, AuthChallengeRequest, AuthChallengeSolution,
+                AuthResult, request::Payload as AuthRequestPayload,
+                response::Payload as AuthResponsePayload,
+            },
+            client_request::Payload as ClientRequestPayload,
+            client_response::Payload as ClientResponsePayload,
+        },
+        shared::ClientInfo as ProtoClientInfo,
+    },
+};
+use ed25519_dalek::Signer as _;
+
+use crate::{
+    storage::StorageError,
+    transport::{ClientTransport, next_request_id},
+};
+
+#[derive(Debug, thiserror::Error)]
+pub enum AuthError {
+    #[error("Auth challenge was not returned by server")]
+    MissingAuthChallenge,
+
+    #[error("Client approval denied by User Agent")]
+    ApprovalDenied,
+
+    #[error("No User Agents online to approve client")]
+    NoUserAgentsOnline,
+
+    #[error("Unexpected auth response payload")]
+    UnexpectedAuthResponse,
+
+    #[error("Signing key storage error")]
+    Storage(#[from] StorageError),
+}
+
+fn map_auth_result(code: i32) -> AuthError {
+    match AuthResult::try_from(code).unwrap_or(AuthResult::Unspecified) {
+        AuthResult::ApprovalDenied => AuthError::ApprovalDenied,
+        AuthResult::NoUserAgentsOnline => AuthError::NoUserAgentsOnline,
+        AuthResult::Unspecified
+        | AuthResult::Success
+        | AuthResult::InvalidKey
+        | AuthResult::InvalidSignature
+        | AuthResult::Internal => AuthError::UnexpectedAuthResponse,
+    }
+}
+
+async fn send_auth_challenge_request(
+    transport: &mut ClientTransport,
+    metadata: ClientMetadata,
+    key: &ed25519_dalek::SigningKey,
+) -> std::result::Result<(), AuthError> {
+    transport
+        .send(ClientRequest {
+            request_id: next_request_id(),
+            payload: Some(ClientRequestPayload::Auth(proto_auth::Request {
+                payload: Some(AuthRequestPayload::ChallengeRequest(AuthChallengeRequest {
+                    pubkey: key.verifying_key().to_bytes().to_vec(),
+                    client_info: Some(ProtoClientInfo {
+                        name: metadata.name,
+                        description: metadata.description,
+                        version: metadata.version,
+                    }),
+                })),
+            })),
+        })
+        .await
+        .map_err(|_| AuthError::UnexpectedAuthResponse)
+}
+
+async fn receive_auth_challenge(
+    transport: &mut ClientTransport,
+) -> std::result::Result<AuthChallenge, AuthError> {
+    let response = transport
+        .recv()
+        .await
+        .map_err(|_| AuthError::MissingAuthChallenge)?;
+
+    let payload = response.payload.ok_or(AuthError::MissingAuthChallenge)?;
+    match payload {
+        ClientResponsePayload::Auth(response) => match response.payload {
+            Some(AuthResponsePayload::Challenge(challenge)) => Ok(challenge),
+            Some(AuthResponsePayload::Result(result)) => Err(map_auth_result(result)),
+            None => Err(AuthError::MissingAuthChallenge),
+        },
+        _ => Err(AuthError::UnexpectedAuthResponse),
+    }
+}
+
+async fn send_auth_challenge_solution(
+    transport: &mut ClientTransport,
+    key: &ed25519_dalek::SigningKey,
+    challenge: AuthChallenge,
+) -> std::result::Result<(), AuthError> {
+    let challenge_payload = format_challenge(challenge.nonce, &challenge.pubkey);
+    let signature = key.sign(&challenge_payload).to_bytes().to_vec();
+
+    transport
+        .send(ClientRequest {
+            request_id: next_request_id(),
+            payload: Some(ClientRequestPayload::Auth(proto_auth::Request {
+                payload: Some(AuthRequestPayload::ChallengeSolution(
+                    AuthChallengeSolution { signature },
+                )),
+            })),
+        })
+        .await
+        .map_err(|_| AuthError::UnexpectedAuthResponse)
+}
+
+async fn receive_auth_confirmation(
+    transport: &mut ClientTransport,
+) -> std::result::Result<(), AuthError> {
+    let response = transport
+        .recv()
+        .await
+        .map_err(|_| AuthError::UnexpectedAuthResponse)?;
+
+    let payload = response.payload.ok_or(AuthError::UnexpectedAuthResponse)?;
+    match payload {
+        ClientResponsePayload::Auth(response) => match response.payload {
+            Some(AuthResponsePayload::Result(result))
+                if AuthResult::try_from(result).ok() == Some(AuthResult::Success) =>
+            {
+                Ok(())
+            }
+            Some(AuthResponsePayload::Result(result)) => Err(map_auth_result(result)),
+            _ => Err(AuthError::UnexpectedAuthResponse),
+        },
+        _ => Err(AuthError::UnexpectedAuthResponse),
+    }
+}
+
+pub(crate) async fn authenticate(
+    transport: &mut ClientTransport,
+    metadata: ClientMetadata,
+    key: &ed25519_dalek::SigningKey,
+) -> std::result::Result<(), AuthError> {
+    send_auth_challenge_request(transport, metadata, key).await?;
+    let challenge = receive_auth_challenge(transport).await?;
+    send_auth_challenge_solution(transport, key, challenge).await?;
+    receive_auth_confirmation(transport).await
+}

server/crates/arbiter-client/src/bin/test_connect.rs

@@ -0,0 +1,44 @@
+use std::io::{self, Write};
+
+use arbiter_client::ArbiterClient;
+use arbiter_proto::{ClientMetadata, url::ArbiterUrl};
+
+#[tokio::main]
+async fn main() {
+    println!("Testing connection to Arbiter server...");
+    print!("Enter ArbiterUrl: ");
+    let _ = io::stdout().flush();
+
+    let mut input = String::new();
+    if let Err(err) = io::stdin().read_line(&mut input) {
+        eprintln!("Failed to read input: {err}");
+        return;
+    }
+
+    let input = input.trim();
+    if input.is_empty() {
+        eprintln!("ArbiterUrl cannot be empty");
+        return;
+    }
+
+    let url = match ArbiterUrl::try_from(input) {
+        Ok(url) => url,
+        Err(err) => {
+            eprintln!("Invalid ArbiterUrl: {err}");
+            return;
+        }
+    };
+
+    println!("{:#?}", url);
+
+    let metadata = ClientMetadata {
+        name: "arbiter-client test_connect".to_string(),
+        description: Some("Manual connection smoke test".to_string()),
+        version: Some(env!("CARGO_PKG_VERSION").to_string()),
+    };
+
+    match ArbiterClient::connect(url, metadata).await {
+        Ok(_) => println!("Connected and authenticated successfully."),
+        Err(err) => eprintln!("Failed to connect: {:#?}", err),
+    }
+}

server/crates/arbiter-client/src/client.rs

@@ -0,0 +1,94 @@
+use arbiter_proto::{
+    ClientMetadata, proto::arbiter_service_client::ArbiterServiceClient, url::ArbiterUrl,
+};
+use std::sync::Arc;
+use tokio::sync::{Mutex, mpsc};
+use tokio_stream::wrappers::ReceiverStream;
+use tonic::transport::ClientTlsConfig;
+
+use crate::{
+    StorageError,
+    auth::{AuthError, authenticate},
+    storage::{FileSigningKeyStorage, SigningKeyStorage},
+    transport::{BUFFER_LENGTH, ClientTransport},
+};
+
+#[cfg(feature = "evm")]
+use crate::wallets::evm::ArbiterEvmWallet;
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("gRPC error")]
+    Grpc(#[from] tonic::Status),
+
+    #[error("Could not establish connection")]
+    Connection(#[from] tonic::transport::Error),
+
+    #[error("Invalid server URI")]
+    InvalidUri(#[from] http::uri::InvalidUri),
+
+    #[error("Invalid CA certificate")]
+    InvalidCaCert(#[from] webpki::Error),
+
+    #[error("Authentication error")]
+    Authentication(#[from] AuthError),
+
+    #[error("Storage error")]
+    Storage(#[from] StorageError),
+}
+
+pub struct ArbiterClient {
+    #[allow(dead_code)]
+    transport: Arc<Mutex<ClientTransport>>,
+}
+
+impl ArbiterClient {
+    pub async fn connect(url: ArbiterUrl, metadata: ClientMetadata) -> Result<Self, Error> {
+        let storage = FileSigningKeyStorage::from_default_location()?;
+        Self::connect_with_storage(url, metadata, &storage).await
+    }
+
+    pub async fn connect_with_storage<S: SigningKeyStorage>(
+        url: ArbiterUrl,
+        metadata: ClientMetadata,
+        storage: &S,
+    ) -> Result<Self, Error> {
+        let key = storage.load_or_create()?;
+        Self::connect_with_key(url, metadata, key).await
+    }
+
+    pub async fn connect_with_key(
+        url: ArbiterUrl,
+        metadata: ClientMetadata,
+        key: ed25519_dalek::SigningKey,
+    ) -> Result<Self, Error> {
+        let anchor = webpki::anchor_from_trusted_cert(&url.ca_cert)?.to_owned();
+        let tls = ClientTlsConfig::new().trust_anchor(anchor);
+
+        let channel =
+            tonic::transport::Channel::from_shared(format!("https://{}:{}", url.host, url.port))?
+                .tls_config(tls)?
+                .connect()
+                .await?;
+
+        let mut client = ArbiterServiceClient::new(channel);
+        let (tx, rx) = mpsc::channel(BUFFER_LENGTH);
+        let response_stream = client.client(ReceiverStream::new(rx)).await?.into_inner();
+
+        let mut transport = ClientTransport {
+            sender: tx,
+            receiver: response_stream,
+        };
+
+        authenticate(&mut transport, metadata, &key).await?;
+
+        Ok(Self {
+            transport: Arc::new(Mutex::new(transport)),
+        })
+    }
+
+    #[cfg(feature = "evm")]
+    pub async fn evm_wallets(&self) -> Result<Vec<ArbiterEvmWallet>, Error> {
+        todo!("fetch EVM wallet list from server")
+    }
+}

server/crates/arbiter-client/src/lib.rs

@@ -1,272 +1,12 @@
-use alloy::{
+mod auth;
-    consensus::SignableTransaction,
+mod client;
-    network::TxSigner,
+mod storage;
-    primitives::{Address, B256, ChainId, Signature},
+mod transport;
-    signers::{Error, Result, Signer},
+pub mod wallets;
-};
-use arbiter_proto::{
-    format_challenge,
-    proto::{
-        arbiter_service_client::ArbiterServiceClient,
-        client::{
-            AuthChallengeRequest, AuthChallengeSolution, ClientRequest, ClientResponse,
-            client_connect_error, client_request::Payload as ClientRequestPayload,
-            client_response::Payload as ClientResponsePayload,
-        },
-        evm::{
-            EvmSignTransactionRequest, evm_sign_transaction_response::Result as SignResponseResult,
-        },
-    },
-    url::ArbiterUrl,
-};
-use async_trait::async_trait;
-use ed25519_dalek::Signer as _;
-use tokio::sync::{Mutex, mpsc};
-use tokio_stream::wrappers::ReceiverStream;
-use tonic::transport::ClientTlsConfig;
 
-#[derive(Debug, thiserror::Error)]
+pub use auth::AuthError;
-pub enum ConnectError {
+pub use client::{ArbiterClient, Error};
-    #[error("Could not establish connection")]
+pub use storage::{FileSigningKeyStorage, SigningKeyStorage, StorageError};
-    Connection(#[from] tonic::transport::Error),
 
-    #[error("Invalid server URI")]
+#[cfg(feature = "evm")]
-    InvalidUri(#[from] http::uri::InvalidUri),
+pub use wallets::evm::{ArbiterEvmSignTransactionError, ArbiterEvmWallet};
-
-    #[error("Invalid CA certificate")]
-    InvalidCaCert(#[from] webpki::Error),
-
-    #[error("gRPC error")]
-    Grpc(#[from] tonic::Status),
-
-    #[error("Auth challenge was not returned by server")]
-    MissingAuthChallenge,
-
-    #[error("Client approval denied by User Agent")]
-    ApprovalDenied,
-
-    #[error("No User Agents online to approve client")]
-    NoUserAgentsOnline,
-
-    #[error("Unexpected auth response payload")]
-    UnexpectedAuthResponse,
-}
-
-#[derive(Debug, thiserror::Error)]
-enum ClientSignError {
-    #[error("Transport channel closed")]
-    ChannelClosed,
-
-    #[error("Connection closed by server")]
-    ConnectionClosed,
-
-    #[error("Invalid response payload")]
-    InvalidResponse,
-
-    #[error("Remote signing was rejected")]
-    Rejected,
-}
-
-struct ClientTransport {
-    sender: mpsc::Sender<ClientRequest>,
-    receiver: tonic::Streaming<ClientResponse>,
-}
-
-impl ClientTransport {
-    async fn send(&mut self, request: ClientRequest) -> std::result::Result<(), ClientSignError> {
-        self.sender
-            .send(request)
-            .await
-            .map_err(|_| ClientSignError::ChannelClosed)
-    }
-
-    async fn recv(&mut self) -> std::result::Result<ClientResponse, ClientSignError> {
-        match self.receiver.message().await {
-            Ok(Some(resp)) => Ok(resp),
-            Ok(None) => Err(ClientSignError::ConnectionClosed),
-            Err(_) => Err(ClientSignError::ConnectionClosed),
-        }
-    }
-}
-
-pub struct ArbiterSigner {
-    transport: Mutex<ClientTransport>,
-    address: Address,
-    chain_id: Option<ChainId>,
-}
-
-impl ArbiterSigner {
-    pub async fn connect_grpc(
-        url: ArbiterUrl,
-        key: ed25519_dalek::SigningKey,
-        address: Address,
-    ) -> std::result::Result<Self, ConnectError> {
-        let anchor = webpki::anchor_from_trusted_cert(&url.ca_cert)?.to_owned();
-        let tls = ClientTlsConfig::new().trust_anchor(anchor);
-
-        // NOTE: We intentionally keep the same URL construction strategy as the user-agent crate
-        // to avoid behavior drift between the two clients.
-        let channel = tonic::transport::Channel::from_shared(format!("{}:{}", url.host, url.port))?
-            .tls_config(tls)?
-            .connect()
-            .await?;
-
-        let mut client = ArbiterServiceClient::new(channel);
-        let (tx, rx) = mpsc::channel(16);
-        let response_stream = client.client(ReceiverStream::new(rx)).await?.into_inner();
-
-        let mut transport = ClientTransport {
-            sender: tx,
-            receiver: response_stream,
-        };
-
-        authenticate(&mut transport, key).await?;
-
-        Ok(Self {
-            transport: Mutex::new(transport),
-            address,
-            chain_id: None,
-        })
-    }
-
-    async fn sign_transaction_via_arbiter(
-        &self,
-        tx: &mut dyn SignableTransaction<Signature>,
-    ) -> Result<Signature> {
-        if let Some(chain_id) = self.chain_id
-            && !tx.set_chain_id_checked(chain_id)
-        {
-            return Err(Error::TransactionChainIdMismatch {
-                signer: chain_id,
-                tx: tx.chain_id().unwrap(),
-            });
-        }
-
-        let mut rlp_transaction = Vec::new();
-        tx.encode_for_signing(&mut rlp_transaction);
-
-        let request = ClientRequest {
-            payload: Some(ClientRequestPayload::EvmSignTransaction(
-                EvmSignTransactionRequest {
-                    wallet_address: self.address.as_slice().to_vec(),
-                    rlp_transaction,
-                },
-            )),
-        };
-
-        let mut transport = self.transport.lock().await;
-        transport.send(request).await.map_err(Error::other)?;
-        let response = transport.recv().await.map_err(Error::other)?;
-
-        let payload = response
-            .payload
-            .ok_or_else(|| Error::other(ClientSignError::InvalidResponse))?;
-
-        let ClientResponsePayload::EvmSignTransaction(sign_response) = payload else {
-            return Err(Error::other(ClientSignError::InvalidResponse));
-        };
-
-        let Some(result) = sign_response.result else {
-            return Err(Error::other(ClientSignError::InvalidResponse));
-        };
-
-        match result {
-            SignResponseResult::Signature(bytes) => {
-                Signature::try_from(bytes.as_slice()).map_err(Error::other)
-            }
-            SignResponseResult::EvalError(_) | SignResponseResult::Error(_) => {
-                Err(Error::other(ClientSignError::Rejected))
-            }
-        }
-    }
-}
-
-async fn authenticate(
-    transport: &mut ClientTransport,
-    key: ed25519_dalek::SigningKey,
-) -> std::result::Result<(), ConnectError> {
-    transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeRequest(
-                AuthChallengeRequest {
-                    pubkey: key.verifying_key().to_bytes().to_vec(),
-                },
-            )),
-        })
-        .await
-        .map_err(|_| ConnectError::UnexpectedAuthResponse)?;
-
-    let response = transport
-        .recv()
-        .await
-        .map_err(|_| ConnectError::MissingAuthChallenge)?;
-
-    let payload = response.payload.ok_or(ConnectError::MissingAuthChallenge)?;
-    match payload {
-        ClientResponsePayload::AuthChallenge(challenge) => {
-            let challenge_payload = format_challenge(challenge.nonce, &challenge.pubkey);
-            let signature = key.sign(&challenge_payload).to_bytes().to_vec();
-
-            transport
-                .send(ClientRequest {
-                    payload: Some(ClientRequestPayload::AuthChallengeSolution(
-                        AuthChallengeSolution { signature },
-                    )),
-                })
-                .await
-                .map_err(|_| ConnectError::UnexpectedAuthResponse)?;
-
-            // Current server flow does not emit `AuthOk` for SDK clients, so we proceed after
-            // sending the solution. If authentication fails, the first business request will return
-            // a `ClientConnectError` or the stream will close.
-            Ok(())
-        }
-        ClientResponsePayload::ClientConnectError(err) => {
-            match client_connect_error::Code::try_from(err.code)
-                .unwrap_or(client_connect_error::Code::Unknown)
-            {
-                client_connect_error::Code::ApprovalDenied => Err(ConnectError::ApprovalDenied),
-                client_connect_error::Code::NoUserAgentsOnline => {
-                    Err(ConnectError::NoUserAgentsOnline)
-                }
-                client_connect_error::Code::Unknown => Err(ConnectError::UnexpectedAuthResponse),
-            }
-        }
-        _ => Err(ConnectError::UnexpectedAuthResponse),
-    }
-}
-
-#[async_trait]
-impl Signer for ArbiterSigner {
-    async fn sign_hash(&self, _hash: &B256) -> Result<Signature> {
-        Err(Error::other(
-            "hash-only signing is not supported for ArbiterSigner; use transaction signing",
-        ))
-    }
-
-    fn address(&self) -> Address {
-        self.address
-    }
-
-    fn chain_id(&self) -> Option<ChainId> {
-        self.chain_id
-    }
-
-    fn set_chain_id(&mut self, chain_id: Option<ChainId>) {
-        self.chain_id = chain_id;
-    }
-}
-
-#[async_trait]
-impl TxSigner<Signature> for ArbiterSigner {
-    fn address(&self) -> Address {
-        self.address
-    }
-
-    async fn sign_transaction(
-        &self,
-        tx: &mut dyn SignableTransaction<Signature>,
-    ) -> Result<Signature> {
-        self.sign_transaction_via_arbiter(tx).await
-    }
-}

server/crates/arbiter-client/src/storage.rs

@@ -0,0 +1,132 @@
+use arbiter_proto::home_path;
+use std::path::{Path, PathBuf};
+
+#[derive(Debug, thiserror::Error)]
+pub enum StorageError {
+    #[error("I/O error")]
+    Io(#[from] std::io::Error),
+
+    #[error("Invalid signing key length in storage: expected {expected} bytes, got {actual} bytes")]
+    InvalidKeyLength { expected: usize, actual: usize },
+}
+
+pub trait SigningKeyStorage {
+    fn load_or_create(&self) -> std::result::Result<ed25519_dalek::SigningKey, StorageError>;
+}
+
+#[derive(Debug, Clone)]
+pub struct FileSigningKeyStorage {
+    path: PathBuf,
+}
+
+impl FileSigningKeyStorage {
+    pub const DEFAULT_FILE_NAME: &str = "sdk_client_ed25519.key";
+
+    pub fn new(path: impl Into<PathBuf>) -> Self {
+        Self { path: path.into() }
+    }
+
+    pub fn from_default_location() -> std::result::Result<Self, StorageError> {
+        Ok(Self::new(home_path()?.join(Self::DEFAULT_FILE_NAME)))
+    }
+
+    fn read_key(path: &Path) -> std::result::Result<ed25519_dalek::SigningKey, StorageError> {
+        let bytes = std::fs::read(path)?;
+        let raw: [u8; 32] =
+            bytes
+                .try_into()
+                .map_err(|v: Vec<u8>| StorageError::InvalidKeyLength {
+                    expected: 32,
+                    actual: v.len(),
+                })?;
+        Ok(ed25519_dalek::SigningKey::from_bytes(&raw))
+    }
+}
+
+impl SigningKeyStorage for FileSigningKeyStorage {
+    fn load_or_create(&self) -> std::result::Result<ed25519_dalek::SigningKey, StorageError> {
+        if let Some(parent) = self.path.parent() {
+            std::fs::create_dir_all(parent)?;
+        }
+
+        if self.path.exists() {
+            return Self::read_key(&self.path);
+        }
+
+        let key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+        let raw_key = key.to_bytes();
+
+        // Use create_new to prevent accidental overwrite if another process creates the key first.
+        match std::fs::OpenOptions::new()
+            .create_new(true)
+            .write(true)
+            .open(&self.path)
+        {
+            Ok(mut file) => {
+                use std::io::Write as _;
+                file.write_all(&raw_key)?;
+                Ok(key)
+            }
+            Err(err) if err.kind() == std::io::ErrorKind::AlreadyExists => {
+                Self::read_key(&self.path)
+            }
+            Err(err) => Err(StorageError::Io(err)),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{FileSigningKeyStorage, SigningKeyStorage, StorageError};
+
+    fn unique_temp_key_path() -> std::path::PathBuf {
+        let nanos = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .expect("clock should be after unix epoch")
+            .as_nanos();
+        std::env::temp_dir().join(format!(
+            "arbiter-client-key-{}-{}.bin",
+            std::process::id(),
+            nanos
+        ))
+    }
+
+    #[test]
+    fn file_storage_creates_and_reuses_key() {
+        let path = unique_temp_key_path();
+        let storage = FileSigningKeyStorage::new(path.clone());
+
+        let key_a = storage
+            .load_or_create()
+            .expect("first load_or_create should create key");
+        let key_b = storage
+            .load_or_create()
+            .expect("second load_or_create should read same key");
+
+        assert_eq!(key_a.to_bytes(), key_b.to_bytes());
+        assert!(path.exists());
+
+        std::fs::remove_file(path).expect("temp key file should be removable");
+    }
+
+    #[test]
+    fn file_storage_rejects_invalid_key_length() {
+        let path = unique_temp_key_path();
+        std::fs::write(&path, [42u8; 31]).expect("should write invalid key file");
+        let storage = FileSigningKeyStorage::new(path.clone());
+
+        let err = storage
+            .load_or_create()
+            .expect_err("storage should reject non-32-byte key file");
+
+        match err {
+            StorageError::InvalidKeyLength { expected, actual } => {
+                assert_eq!(expected, 32);
+                assert_eq!(actual, 31);
+            }
+            other => panic!("unexpected error: {other:?}"),
+        }
+
+        std::fs::remove_file(path).expect("temp key file should be removable");
+    }
+}

server/crates/arbiter-client/src/transport.rs

@@ -0,0 +1,44 @@
+use arbiter_proto::proto::client::{ClientRequest, ClientResponse};
+use std::sync::atomic::{AtomicI32, Ordering};
+use tokio::sync::mpsc;
+
+pub(crate) const BUFFER_LENGTH: usize = 16;
+static NEXT_REQUEST_ID: AtomicI32 = AtomicI32::new(1);
+
+pub(crate) fn next_request_id() -> i32 {
+    NEXT_REQUEST_ID.fetch_add(1, Ordering::Relaxed)
+}
+
+#[derive(Debug, thiserror::Error)]
+pub(crate) enum ClientSignError {
+    #[error("Transport channel closed")]
+    ChannelClosed,
+
+    #[error("Connection closed by server")]
+    ConnectionClosed,
+}
+
+pub(crate) struct ClientTransport {
+    pub(crate) sender: mpsc::Sender<ClientRequest>,
+    pub(crate) receiver: tonic::Streaming<ClientResponse>,
+}
+
+impl ClientTransport {
+    pub(crate) async fn send(
+        &mut self,
+        request: ClientRequest,
+    ) -> std::result::Result<(), ClientSignError> {
+        self.sender
+            .send(request)
+            .await
+            .map_err(|_| ClientSignError::ChannelClosed)
+    }
+
+    pub(crate) async fn recv(&mut self) -> std::result::Result<ClientResponse, ClientSignError> {
+        match self.receiver.message().await {
+            Ok(Some(resp)) => Ok(resp),
+            Ok(None) => Err(ClientSignError::ConnectionClosed),
+            Err(_) => Err(ClientSignError::ConnectionClosed),
+        }
+    }
+}

server/crates/arbiter-client/src/wallets/evm.rs

@@ -0,0 +1,192 @@
+use alloy::{
+    consensus::SignableTransaction,
+    network::TxSigner,
+    primitives::{Address, B256, ChainId, Signature},
+    signers::{Error, Result, Signer},
+};
+use async_trait::async_trait;
+use std::sync::Arc;
+use tokio::sync::Mutex;
+
+use arbiter_proto::proto::{
+    client::{
+        ClientRequest,
+        client_request::Payload as ClientRequestPayload,
+        client_response::Payload as ClientResponsePayload,
+        evm::{
+            self as proto_evm, request::Payload as EvmRequestPayload,
+            response::Payload as EvmResponsePayload,
+        },
+    },
+    evm::{
+        EvmSignTransactionRequest,
+        evm_sign_transaction_response::Result as EvmSignTransactionResult,
+    },
+    shared::evm::TransactionEvalError,
+};
+
+use crate::transport::{ClientTransport, next_request_id};
+
+/// A typed error payload returned by [`ArbiterEvmWallet`] transaction signing.
+///
+/// This is wrapped into `alloy::signers::Error::Other`, so consumers can downcast by [`TryFrom`] and
+/// interpret the concrete policy evaluation failure instead of parsing strings.
+#[derive(Debug, thiserror::Error)]
+#[non_exhaustive]
+pub enum ArbiterEvmSignTransactionError {
+    #[error("transaction rejected by policy: {0:?}")]
+    PolicyEval(TransactionEvalError),
+}
+
+impl<'a> TryFrom<&'a Error> for &'a ArbiterEvmSignTransactionError {
+    type Error = ();
+
+    fn try_from(value: &'a Error) -> Result<Self, Self::Error> {
+        if let Error::Other(inner) = value
+            && let Some(eval_error) = inner.downcast_ref()
+        {
+            Ok(eval_error)
+        } else {
+            Err(())
+        }
+    }
+}
+
+pub struct ArbiterEvmWallet {
+    transport: Arc<Mutex<ClientTransport>>,
+    address: Address,
+    chain_id: Option<ChainId>,
+}
+
+impl ArbiterEvmWallet {
+    pub(crate) fn new(transport: Arc<Mutex<ClientTransport>>, address: Address) -> Self {
+        Self {
+            transport,
+            address,
+            chain_id: None,
+        }
+    }
+
+    pub fn address(&self) -> Address {
+        self.address
+    }
+
+    pub fn with_chain_id(mut self, chain_id: ChainId) -> Self {
+        self.chain_id = Some(chain_id);
+        self
+    }
+
+    fn validate_chain_id(&self, tx: &mut dyn SignableTransaction<Signature>) -> Result<()> {
+        if let Some(chain_id) = self.chain_id
+            && !tx.set_chain_id_checked(chain_id)
+        {
+            return Err(Error::TransactionChainIdMismatch {
+                signer: chain_id,
+                tx: tx.chain_id().unwrap(),
+            });
+        }
+
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl Signer for ArbiterEvmWallet {
+    async fn sign_hash(&self, _hash: &B256) -> Result<Signature> {
+        Err(Error::other(
+            "hash-only signing is not supported for ArbiterEvmWallet; use transaction signing",
+        ))
+    }
+
+    fn address(&self) -> Address {
+        self.address
+    }
+
+    fn chain_id(&self) -> Option<ChainId> {
+        self.chain_id
+    }
+
+    fn set_chain_id(&mut self, chain_id: Option<ChainId>) {
+        self.chain_id = chain_id;
+    }
+}
+
+#[async_trait]
+impl TxSigner<Signature> for ArbiterEvmWallet {
+    fn address(&self) -> Address {
+        self.address
+    }
+
+    async fn sign_transaction(
+        &self,
+        tx: &mut dyn SignableTransaction<Signature>,
+    ) -> Result<Signature> {
+        self.validate_chain_id(tx)?;
+
+        let mut transport = self.transport.lock().await;
+        let request_id = next_request_id();
+        let rlp_transaction = tx.encoded_for_signing();
+
+        transport
+            .send(ClientRequest {
+                request_id,
+                payload: Some(ClientRequestPayload::Evm(proto_evm::Request {
+                    payload: Some(EvmRequestPayload::SignTransaction(
+                        EvmSignTransactionRequest {
+                            wallet_address: self.address.to_vec(),
+                            rlp_transaction,
+                        },
+                    )),
+                })),
+            })
+            .await
+            .map_err(|_| Error::other("failed to send evm sign transaction request"))?;
+
+        let response = transport
+            .recv()
+            .await
+            .map_err(|_| Error::other("failed to receive evm sign transaction response"))?;
+
+        if response.request_id != Some(request_id) {
+            return Err(Error::other(
+                "received mismatched response id for evm sign transaction",
+            ));
+        }
+
+        let payload = response
+            .payload
+            .ok_or_else(|| Error::other("missing evm sign transaction response payload"))?;
+
+        let ClientResponsePayload::Evm(proto_evm::Response {
+            payload: Some(payload),
+        }) = payload
+        else {
+            return Err(Error::other(
+                "unexpected response payload for evm sign transaction request",
+            ));
+        };
+
+        let EvmResponsePayload::SignTransaction(response) = payload else {
+            return Err(Error::other(
+                "unexpected evm response payload for sign transaction request",
+            ));
+        };
+
+        let result = response
+            .result
+            .ok_or_else(|| Error::other("missing evm sign transaction result"))?;
+
+        match result {
+            EvmSignTransactionResult::Signature(signature) => {
+                Signature::try_from(signature.as_slice())
+                    .map_err(|_| Error::other("invalid signature returned by server"))
+            }
+            EvmSignTransactionResult::EvalError(eval_error) => Err(Error::other(
+                ArbiterEvmSignTransactionError::PolicyEval(eval_error),
+            )),
+            EvmSignTransactionResult::Error(code) => Err(Error::other(format!(
+                "server failed to sign transaction with error code {code}"
+            ))),
+        }
+    }
+}

server/crates/arbiter-client/src/wallets/mod.rs

@@ -0,0 +1,2 @@
+#[cfg(feature = "evm")]
+pub mod evm;

server/crates/arbiter-proto/Cargo.toml

@@ -10,7 +10,7 @@ tonic.workspace = true
 tokio.workspace = true
 futures.workspace = true
 hex = "0.4.3"
-tonic-prost = "0.14.3"
+tonic-prost = "0.14.5"
 prost = "0.14.3"
 kameo.workspace = true
 url = "2.5.8"
@@ -21,9 +21,10 @@ base64 = "0.22.1"
 prost-types.workspace = true
 tracing.workspace = true
 async-trait.workspace = true
+tokio-stream.workspace = true
 
 [build-dependencies]
-tonic-prost-build = "0.14.3"
+tonic-prost-build = "0.14.5"
 protoc-bin-vendored = "3"
 
 [dev-dependencies]
@@ -33,5 +34,3 @@ rcgen.workspace = true
 
 [package.metadata.cargo-shear]
 ignored = ["tonic-prost", "prost", "kameo"]
-
-

server/crates/arbiter-proto/build.rs

@@ -3,12 +3,6 @@ use tonic_prost_build::configure;
 static PROTOBUF_DIR: &str = "../../../protobufs";
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    if std::env::var("PROTOC").is_err() {
-        println!("cargo:warning=PROTOC environment variable not set, using vendored protoc");
-        let protoc = protoc_bin_vendored::protoc_bin_path().unwrap();
-        unsafe { std::env::set_var("PROTOC", protoc) };
-    }
-
     println!("cargo::rerun-if-changed={PROTOBUF_DIR}");
 
     configure()

server/crates/arbiter-proto/src/lib.rs

@@ -6,12 +6,56 @@ use base64::{Engine, prelude::BASE64_STANDARD};
 pub mod proto {
     tonic::include_proto!("arbiter");
 
+    pub mod shared {
+        tonic::include_proto!("arbiter.shared");
+
+        pub mod evm {
+            tonic::include_proto!("arbiter.shared.evm");
+        }
+    }
+
     pub mod user_agent {
         tonic::include_proto!("arbiter.user_agent");
+
+        pub mod auth {
+            tonic::include_proto!("arbiter.user_agent.auth");
+        }
+
+        pub mod evm {
+            tonic::include_proto!("arbiter.user_agent.evm");
+        }
+
+        pub mod sdk_client {
+            tonic::include_proto!("arbiter.user_agent.sdk_client");
+        }
+
+        pub mod vault {
+            tonic::include_proto!("arbiter.user_agent.vault");
+
+            pub mod bootstrap {
+                tonic::include_proto!("arbiter.user_agent.vault.bootstrap");
+            }
+
+            pub mod unseal {
+                tonic::include_proto!("arbiter.user_agent.vault.unseal");
+            }
+        }
     }
 
     pub mod client {
         tonic::include_proto!("arbiter.client");
+
+        pub mod auth {
+            tonic::include_proto!("arbiter.client.auth");
+        }
+
+        pub mod evm {
+            tonic::include_proto!("arbiter.client.evm");
+        }
+
+        pub mod vault {
+            tonic::include_proto!("arbiter.client.vault");
+        }
     }
 
     pub mod evm {
@@ -19,6 +63,13 @@ pub mod proto {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ClientMetadata {
+    pub name: String,
+    pub description: Option<String>,
+    pub version: Option<String>,
+}
+
 pub static BOOTSTRAP_PATH: &str = "bootstrap_token";
 
 pub fn home_path() -> Result<std::path::PathBuf, std::io::Error> {

server/crates/arbiter-proto/src/transport.rs

@@ -1,78 +1,59 @@
-//! Transport-facing abstractions for protocol/session code.
+//! Transport-facing abstractions shared by protocol/session code.
 //!
-//! This module separates three concerns:
+//! This module defines a small set of transport traits that actors and other
+//! protocol code can depend on without knowing anything about the concrete
+//! transport underneath.
 //!
-//! - protocol/session logic wants a small duplex interface ([`Bi`])
+//! The abstraction is split into:
-//! - transport adapters push concrete stream items to an underlying IO layer
+//! - [`Sender`] for outbound delivery
-//! - transport boundaries translate between protocol-facing and transport-facing
+//! - [`Receiver`] for inbound delivery
-//!   item types via direction-specific converters
+//! - [`Bi`] as the combined duplex form (`Sender + Receiver`)
 //!
-//! [`Bi`] is intentionally minimal and transport-agnostic:
+//! This split lets code depend only on the half it actually needs. For
-//! - [`Bi::recv`] yields inbound protocol messages
+//! example, some actor/session code only sends out-of-band messages, while
-//! - [`Bi::send`] accepts outbound protocol/domain items
+//! auth/state-machine code may need full duplex access.
+//!
+//! [`Bi`] remains intentionally minimal and transport-agnostic:
+//! - [`Receiver::recv`] yields inbound messages
+//! - [`Sender::send`] accepts outbound messages
+//!
+//! Transport-specific adapters, including protobuf or gRPC bridges, live in the
+//! crates that own those boundaries rather than in `arbiter-proto`.
+//!
+//! [`Bi`] deliberately does not model request/response correlation. Some
+//! transports may carry multiplexed request/response traffic, some may emit
+//! out-of-band messages, and some may be one-message-at-a-time state machines.
+//! Correlation concerns such as request IDs, pending response maps, and
+//! out-of-band routing belong in the adapter or connection layer built on top
+//! of [`Bi`], not in this abstraction itself.
 //!
 //! # Generic Ordering Rule
 //!
-//! This module uses a single convention consistently: when a type or trait is
+//! This module consistently uses `Inbound` first and `Outbound` second in
-//! parameterized by protocol message directions, the generic parameters are
+//! generic parameter lists.
-//! declared as `Inbound` first, then `Outbound`.
 //!
-//! For [`Bi`], that means `Bi<Inbound, Outbound>`:
+//! For [`Receiver`], [`Sender`], and [`Bi`], this means:
+//! - `Receiver<Inbound>`
+//! - `Sender<Outbound>`
+//! - `Bi<Inbound, Outbound>`
+//!
+//! Concretely, for [`Bi`]:
 //! - `recv() -> Option<Inbound>`
 //! - `send(Outbound)`
 //!
-//! For adapter types that are parameterized by direction-specific converters,
+//! [`expect_message`] is a small helper for linear protocol steps: it reads one
-//! inbound-related converter parameters are declared before outbound-related
+//! inbound message from a transport and extracts a typed value from it, failing
-//! converter parameters.
+//! if the channel closes or the message shape is not what the caller expected.
 //!
-//! [`RecvConverter`] and [`SendConverter`] are infallible conversion traits used
+//! [`DummyTransport`] is a no-op implementation useful for tests and local
-//! by adapters to map between protocol-facing and transport-facing item types.
+//! actor execution where no real stream exists.
-//! The traits themselves are not result-aware; adapters decide how transport
-//! errors are handled before (or instead of) conversion.
-//!
-//! [`grpc::GrpcAdapter`] combines:
-//! - a tonic inbound stream
-//! - a Tokio sender for outbound transport items
-//! - a [`RecvConverter`] for the receive path
-//! - a [`SendConverter`] for the send path
-//!
-//! [`DummyTransport`] is a no-op implementation useful for tests and local actor
-//! execution where no real network stream exists.
-//!
-//! # Component Interaction
-//!
-//! ```text
-//! inbound (network -> protocol)
-//! ============================
-//!
-//! tonic::Streaming<RecvTransport>
-//!     -> grpc::GrpcAdapter::recv()
-//!          |
-//!          +--> on `Ok(item)`: RecvConverter::convert(RecvTransport) -> Inbound
-//!          +--> on `Err(status)`: log error and close stream (`None`)
-//!     -> Bi::recv()
-//!     -> protocol/session actor
-//!
-//! outbound (protocol -> network)
-//! ==============================
-//!
-//! protocol/session actor
-//!     -> Bi::send(Outbound)
-//!     -> grpc::GrpcAdapter::send()
-//!          |
-//!          +--> SendConverter::convert(Outbound) -> SendTransport
-//!     -> Tokio mpsc::Sender<SendTransport>
-//!     -> tonic response stream
-//! ```
 //!
 //! # Design Notes
 //!
-//! - `send()` returns [`Error`] only for transport delivery failures (for
+//! - [`Bi::send`] returns [`Error`] only for transport delivery failures, such
-//!   example, when the outbound channel is closed).
+//!   as a closed outbound channel.
-//! - [`grpc::GrpcAdapter`] logs tonic receive errors and treats them as stream
+//! - [`Bi::recv`] returns `None` when the underlying transport closes.
-//!   closure (`None`).
+//! - Message translation is intentionally out of scope for this module.
-//! - When protocol-facing and transport-facing types are identical, use
-//!   [`IdentityRecvConverter`] / [`IdentitySendConverter`].
 
 use std::marker::PhantomData;
 
@@ -102,172 +83,35 @@ where
     extractor(msg).ok_or(Error::UnexpectedMessage)
 }
 
-/// Minimal bidirectional transport abstraction used by protocol code.
-///
-/// `Bi<Inbound, Outbound>` models a duplex channel with:
-/// - inbound items of type `Inbound` read via [`Bi::recv`]
-/// - outbound items of type `Outbound` written via [`Bi::send`]
 #[async_trait]
-pub trait Bi<Inbound, Outbound>: Send + Sync + 'static {
+pub trait Sender<Outbound>: Send + Sync {
     async fn send(&mut self, item: Outbound) -> Result<(), Error>;
+}
 
+#[async_trait]
+pub trait Receiver<Inbound>: Send + Sync {
     async fn recv(&mut self) -> Option<Inbound>;
 }
 
-/// Converts transport-facing inbound items into protocol-facing inbound items.
+/// Minimal bidirectional transport abstraction used by protocol code.
-pub trait RecvConverter: Send + Sync + 'static {
+///
-    type Input;
+/// `Bi<Inbound, Outbound>` is the combined duplex form of [`Sender`] and
-    type Output;
+/// [`Receiver`].
+///
+/// It models a channel with:
+/// - inbound items of type `Inbound` read via [`Bi::recv`]
+/// - outbound items of type `Outbound` written via [`Bi::send`]
+///
+/// It does not imply request/response sequencing, one-at-a-time exchange, or
+/// any built-in correlation mechanism between inbound and outbound items.
+pub trait Bi<Inbound, Outbound>: Sender<Outbound> + Receiver<Inbound> + Send + Sync {}
 
-    fn convert(&self, item: Self::Input) -> Self::Output;
+pub trait SplittableBi<Inbound, Outbound>: Bi<Inbound, Outbound> {
-}
+    type Sender: Sender<Outbound>;
+    type Receiver: Receiver<Inbound>;
 
-/// Converts protocol/domain outbound items into transport-facing outbound items.
+    fn split(self) -> (Self::Sender, Self::Receiver);
-pub trait SendConverter: Send + Sync + 'static {
+    fn from_parts(sender: Self::Sender, receiver: Self::Receiver) -> Self;
-    type Input;
-    type Output;
-
-    fn convert(&self, item: Self::Input) -> Self::Output;
-}
-
-/// A [`RecvConverter`] that forwards values unchanged.
-pub struct IdentityRecvConverter<T> {
-    _marker: PhantomData<T>,
-}
-
-impl<T> IdentityRecvConverter<T> {
-    pub fn new() -> Self {
-        Self {
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<T> Default for IdentityRecvConverter<T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<T> RecvConverter for IdentityRecvConverter<T>
-where
-    T: Send + Sync + 'static,
-{
-    type Input = T;
-    type Output = T;
-
-    fn convert(&self, item: Self::Input) -> Self::Output {
-        item
-    }
-}
-
-/// A [`SendConverter`] that forwards values unchanged.
-pub struct IdentitySendConverter<T> {
-    _marker: PhantomData<T>,
-}
-
-impl<T> IdentitySendConverter<T> {
-    pub fn new() -> Self {
-        Self {
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<T> Default for IdentitySendConverter<T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<T> SendConverter for IdentitySendConverter<T>
-where
-    T: Send + Sync + 'static,
-{
-    type Input = T;
-    type Output = T;
-
-    fn convert(&self, item: Self::Input) -> Self::Output {
-        item
-    }
-}
-
-/// gRPC-specific transport adapters and helpers.
-pub mod grpc {
-    use async_trait::async_trait;
-    use futures::StreamExt;
-    use tokio::sync::mpsc;
-    use tonic::Streaming;
-
-    use super::{Bi, Error, RecvConverter, SendConverter};
-
-    /// [`Bi`] adapter backed by a tonic gRPC bidirectional stream.
-    ///
-    /// Tonic receive errors are logged and treated as stream closure (`None`).
-    /// The receive converter is only invoked for successful inbound transport
-    /// items.
-    pub struct GrpcAdapter<InboundConverter, OutboundConverter>
-    where
-        InboundConverter: RecvConverter,
-        OutboundConverter: SendConverter,
-    {
-        sender: mpsc::Sender<OutboundConverter::Output>,
-        receiver: Streaming<InboundConverter::Input>,
-        inbound_converter: InboundConverter,
-        outbound_converter: OutboundConverter,
-    }
-
-    impl<InboundTransport, Inbound, InboundConverter, OutboundConverter>
-        GrpcAdapter<InboundConverter, OutboundConverter>
-    where
-        InboundConverter: RecvConverter<Input = InboundTransport, Output = Inbound>,
-        OutboundConverter: SendConverter,
-    {
-        pub fn new(
-            sender: mpsc::Sender<OutboundConverter::Output>,
-            receiver: Streaming<InboundTransport>,
-            inbound_converter: InboundConverter,
-            outbound_converter: OutboundConverter,
-        ) -> Self {
-            Self {
-                sender,
-                receiver,
-                inbound_converter,
-                outbound_converter,
-            }
-        }
-    }
-
-    #[async_trait]
-    impl<InboundConverter, OutboundConverter> Bi<InboundConverter::Output, OutboundConverter::Input>
-        for GrpcAdapter<InboundConverter, OutboundConverter>
-    where
-        InboundConverter: RecvConverter,
-        OutboundConverter: SendConverter,
-        OutboundConverter::Input: Send + 'static,
-        OutboundConverter::Output: Send + 'static,
-    {
-        #[tracing::instrument(level = "trace", skip(self, item))]
-        async fn send(&mut self, item: OutboundConverter::Input) -> Result<(), Error> {
-            let outbound = self.outbound_converter.convert(item);
-            self.sender
-                .send(outbound)
-                .await
-                .map_err(|_| Error::ChannelClosed)
-        }
-
-        #[tracing::instrument(level = "trace", skip(self))]
-        async fn recv(&mut self) -> Option<InboundConverter::Output> {
-            match self.receiver.next().await {
-                Some(Ok(item)) => Some(self.inbound_converter.convert(item)),
-                Some(Err(error)) => {
-                    tracing::error!(error = ?error, "grpc transport recv failed; closing stream");
-                    None
-                }
-                None => None,
-            }
-        }
-    }
 }
 
 /// No-op [`Bi`] transport for tests and manual actor usage.
@@ -278,22 +122,16 @@ pub struct DummyTransport<Inbound, Outbound> {
     _marker: PhantomData<(Inbound, Outbound)>,
 }
 
-impl<Inbound, Outbound> DummyTransport<Inbound, Outbound> {
+impl<Inbound, Outbound> Default for DummyTransport<Inbound, Outbound> {
-    pub fn new() -> Self {
+    fn default() -> Self {
         Self {
             _marker: PhantomData,
         }
     }
 }
 
-impl<Inbound, Outbound> Default for DummyTransport<Inbound, Outbound> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
 #[async_trait]
-impl<Inbound, Outbound> Bi<Inbound, Outbound> for DummyTransport<Inbound, Outbound>
+impl<Inbound, Outbound> Sender<Outbound> for DummyTransport<Inbound, Outbound>
 where
     Inbound: Send + Sync + 'static,
     Outbound: Send + Sync + 'static,
@@ -301,9 +139,25 @@ where
     async fn send(&mut self, _item: Outbound) -> Result<(), Error> {
         Ok(())
     }
+}
 
+#[async_trait]
+impl<Inbound, Outbound> Receiver<Inbound> for DummyTransport<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
     async fn recv(&mut self) -> Option<Inbound> {
         std::future::pending::<()>().await;
         None
     }
 }
+
+impl<Inbound, Outbound> Bi<Inbound, Outbound> for DummyTransport<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+}
+
+pub mod grpc;

server/crates/arbiter-proto/src/transport/grpc.rs

@@ -0,0 +1,106 @@
+use async_trait::async_trait;
+use futures::StreamExt;
+use tokio::sync::mpsc;
+use tokio_stream::wrappers::ReceiverStream;
+
+use super::{Bi, Receiver, Sender};
+
+pub struct GrpcSender<Outbound> {
+    tx: mpsc::Sender<Result<Outbound, tonic::Status>>,
+}
+
+#[async_trait]
+impl<Outbound> Sender<Result<Outbound, tonic::Status>> for GrpcSender<Outbound>
+where
+    Outbound: Send + Sync + 'static,
+{
+    async fn send(&mut self, item: Result<Outbound, tonic::Status>) -> Result<(), super::Error> {
+        self.tx
+            .send(item)
+            .await
+            .map_err(|_| super::Error::ChannelClosed)
+    }
+}
+
+pub struct GrpcReceiver<Inbound> {
+    rx: tonic::Streaming<Inbound>,
+}
+#[async_trait]
+impl<Inbound> Receiver<Result<Inbound, tonic::Status>> for GrpcReceiver<Inbound>
+where
+    Inbound: Send + Sync + 'static,
+{
+    async fn recv(&mut self) -> Option<Result<Inbound, tonic::Status>> {
+        self.rx.next().await
+    }
+}
+
+pub struct GrpcBi<Inbound, Outbound> {
+    sender: GrpcSender<Outbound>,
+    receiver: GrpcReceiver<Inbound>,
+}
+
+impl<Inbound, Outbound> GrpcBi<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+    pub fn from_bi_stream(
+        receiver: tonic::Streaming<Inbound>,
+    ) -> (Self, ReceiverStream<Result<Outbound, tonic::Status>>) {
+        let (tx, rx) = mpsc::channel(10);
+        let sender = GrpcSender { tx };
+        let receiver = GrpcReceiver { rx: receiver };
+        let bi = GrpcBi { sender, receiver };
+        (bi, ReceiverStream::new(rx))
+    }
+}
+
+#[async_trait]
+impl<Inbound, Outbound> Sender<Result<Outbound, tonic::Status>> for GrpcBi<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+    async fn send(&mut self, item: Result<Outbound, tonic::Status>) -> Result<(), super::Error> {
+        self.sender.send(item).await
+    }
+}
+
+#[async_trait]
+impl<Inbound, Outbound> Receiver<Result<Inbound, tonic::Status>> for GrpcBi<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+    async fn recv(&mut self) -> Option<Result<Inbound, tonic::Status>> {
+        self.receiver.recv().await
+    }
+}
+
+impl<Inbound, Outbound> Bi<Result<Inbound, tonic::Status>, Result<Outbound, tonic::Status>>
+    for GrpcBi<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+}
+
+impl<Inbound, Outbound>
+    super::SplittableBi<Result<Inbound, tonic::Status>, Result<Outbound, tonic::Status>>
+    for GrpcBi<Inbound, Outbound>
+where
+    Inbound: Send + Sync + 'static,
+    Outbound: Send + Sync + 'static,
+{
+    type Sender = GrpcSender<Outbound>;
+    type Receiver = GrpcReceiver<Inbound>;
+
+    fn split(self) -> (Self::Sender, Self::Receiver) {
+        (self.sender, self.receiver)
+    }
+
+    fn from_parts(sender: Self::Sender, receiver: Self::Receiver) -> Self {
+        GrpcBi { sender, receiver }
+    }
+}

server/crates/arbiter-proto/src/url.rs

@@ -7,6 +7,7 @@ const ARBITER_URL_SCHEME: &str = "arbiter";
 const CERT_QUERY_KEY: &str = "cert";
 const BOOTSTRAP_TOKEN_QUERY_KEY: &str = "bootstrap_token";
 
+#[derive(Debug, Clone)]
 pub struct ArbiterUrl {
     pub host: String,
     pub port: u16,

server/crates/arbiter-server/Cargo.toml

@@ -9,8 +9,8 @@ license = "Apache-2.0"
 workspace = true
 
 [dependencies]
-diesel = { version = "2.3.6", features = ["chrono", "returning_clauses_for_sqlite_3_35", "serde_json", "time", "uuid"] }
+diesel = { version = "2.3.7", features = ["chrono", "returning_clauses_for_sqlite_3_35", "serde_json", "time", "uuid"] }
-diesel-async = { version = "0.7.4", features = [
+diesel-async = { version = "0.8.0", features = [
     "bb8",
     "migrations",
     "sqlite",
@@ -25,8 +25,8 @@ tonic.features = ["tls-aws-lc"]
 tokio.workspace = true
 rustls.workspace = true
 smlang.workspace = true
-miette.workspace = true
 thiserror.workspace = true
+fatality = "0.1.1"
 diesel_migrations = { version = "2.3.1", features = ["sqlite"] }
 async-trait.workspace = true
 secrecy = "0.10.3"
@@ -43,14 +43,17 @@ x25519-dalek.workspace = true
 chacha20poly1305 = { version = "0.10.1", features = ["std"] }
 argon2 = { version = "0.5.3", features = ["zeroize"] }
 restructed = "0.2.2"
-strum = { version = "0.27.2", features = ["derive"] }
+strum = { version = "0.28.0", features = ["derive"] }
 pem = "3.0.6"
 k256.workspace = true
 rsa.workspace = true
 sha2.workspace = true
+hmac = "0.12"
 spki.workspace = true
 alloy.workspace = true
+prost-types.workspace = true
 arbiter-tokens-registry.path = "../arbiter-tokens-registry"
+anyhow = "1.0.102"
 
 [dev-dependencies]
 insta = "1.46.3"

server/crates/arbiter-server/migrations/2026-02-14-171124-0000_init/up.sql

@@ -40,25 +40,52 @@ create table if not exists arbiter_settings (
     tls_id integer references tls_history (id) on delete RESTRICT
 ) STRICT;
 
-insert into arbiter_settings (id) values (1) on conflict do nothing; -- ensure singleton row exists
+insert into arbiter_settings (id) values (1) on conflict do nothing;
+-- ensure singleton row exists
 
 create table if not exists useragent_client (
     id integer not null primary key,
     nonce integer not null default(1), -- used for auth challenge
     public_key blob not null,
+    pubkey_integrity_tag blob,
     key_type integer not null default(1), -- 1=Ed25519, 2=ECDSA(secp256k1)
     created_at integer not null default(unixepoch ('now')),
     updated_at integer not null default(unixepoch ('now'))
 ) STRICT;
+create unique index if not exists uniq_useragent_client_public_key on useragent_client (public_key, key_type);
+
+create table if not exists client_metadata (
+    id integer not null primary key,
+    name text not null, -- human-readable name for the client
+    description text, -- optional description for the client
+    version text, -- client version for tracking and debugging
+    created_at integer not null default(unixepoch ('now'))
+) STRICT;
+
+-- created to track history of changes
+create table if not exists client_metadata_history (
+    id integer not null primary key,
+    metadata_id integer not null references client_metadata (id) on delete cascade,
+    client_id integer not null references program_client (id) on delete cascade,
+    created_at integer not null default(unixepoch ('now'))
+) STRICT;
+
+create unique index if not exists uniq_metadata_binding_client on client_metadata_history (client_id);
 
 create table if not exists program_client (
     id integer not null primary key,
     nonce integer not null default(1), -- used for auth challenge
     public_key blob not null,
+    metadata_id integer not null references client_metadata (id) on delete cascade,
     created_at integer not null default(unixepoch ('now')),
     updated_at integer not null default(unixepoch ('now'))
 ) STRICT;
 
+create unique index if not exists program_client_public_key_unique
+    on program_client (public_key);
+
+create unique index if not exists uniq_program_client_public_key on program_client (public_key);
+
 create table if not exists evm_wallet (
     id integer not null primary key,
     address blob not null, -- 20-byte Ethereum address
@@ -67,8 +94,18 @@ create table if not exists evm_wallet (
 ) STRICT;
 
 create unique index if not exists uniq_evm_wallet_address on evm_wallet (address);
+
 create unique index if not exists uniq_evm_wallet_aead on evm_wallet (aead_encrypted_id);
 
+create table if not exists evm_wallet_access (
+    id integer not null primary key,
+    wallet_id integer not null references evm_wallet (id) on delete cascade,
+    client_id integer not null references program_client (id) on delete cascade,
+    created_at integer not null default(unixepoch ('now'))
+) STRICT;
+
+create unique index if not exists uniq_wallet_access on evm_wallet_access (wallet_id, client_id);
+
 create table if not exists evm_ether_transfer_limit (
     id integer not null primary key,
     window_secs integer not null, -- window duration in seconds
@@ -78,8 +115,7 @@ create table if not exists evm_ether_transfer_limit (
 -- Shared grant properties: client scope, timeframe, fee caps, and rate limit
 create table if not exists evm_basic_grant (
     id integer not null primary key,
-    wallet_id integer not null references evm_wallet(id) on delete restrict, 
+    wallet_access_id integer not null references evm_wallet_access (id) on delete restrict,
-    client_id integer not null references program_client(id) on delete restrict,
     chain_id integer not null, -- EIP-155 chain ID
     valid_from integer, -- unix timestamp (seconds), null = no lower bound
     valid_until integer, -- unix timestamp (seconds), null = no upper bound
@@ -88,28 +124,27 @@ create table if not exists evm_basic_grant (
     rate_limit_count integer, -- max transactions in window, null = unlimited
     rate_limit_window_secs integer, -- window duration in seconds, null = unlimited
     revoked_at integer, -- unix timestamp when revoked, null = still active
-    created_at integer not null default(unixepoch('now'))
+    created_at integer not null default(unixepoch ('now'))
 ) STRICT;
 
 -- Shared transaction log for all EVM grants, used for rate limit tracking and auditing
 create table if not exists evm_transaction_log (
     id integer not null primary key,
-    grant_id integer not null references evm_basic_grant(id) on delete restrict,
+    wallet_access_id integer not null references evm_wallet_access (id) on delete restrict,
-    client_id integer not null references program_client(id) on delete restrict,
+    grant_id integer not null references evm_basic_grant (id) on delete restrict,
-    wallet_id integer not null references evm_wallet(id) on delete restrict,
     chain_id integer not null,
     eth_value blob not null, -- always present on any EVM tx
-    signed_at integer not null default(unixepoch('now'))
+    signed_at integer not null default(unixepoch ('now'))
 ) STRICT;
 
-create index if not exists idx_evm_basic_grant_wallet_chain on evm_basic_grant(client_id, wallet_id, chain_id);
+create index if not exists idx_evm_basic_grant_access_chain on evm_basic_grant (wallet_access_id, chain_id);
 
 -- ===============================
 -- ERC20 token transfer grant
 -- ===============================
 create table if not exists evm_token_transfer_grant (
     id integer not null primary key,
-    basic_grant_id integer not null unique references evm_basic_grant(id) on delete cascade,
+    basic_grant_id integer not null unique references evm_basic_grant (id) on delete cascade,
     token_contract blob not null, -- 20-byte ERC20 contract address
     receiver blob -- 20-byte recipient address or null if every recipient allowed
 ) STRICT;
@@ -117,7 +152,7 @@ create table if not exists evm_token_transfer_grant (
 -- Per-window volume limits for token transfer grants
 create table if not exists evm_token_transfer_volume_limit (
     id integer not null primary key,
-    grant_id integer not null references evm_token_transfer_grant(id) on delete cascade,
+    grant_id integer not null references evm_token_transfer_grant (id) on delete cascade,
     window_secs integer not null, -- window duration in seconds
     max_volume blob not null -- big-endian 32-byte U256
 ) STRICT;
@@ -125,35 +160,35 @@ create table if not exists evm_token_transfer_volume_limit (
 -- Log table for token transfer grant usage
 create table if not exists evm_token_transfer_log (
     id integer not null primary key,
-    grant_id integer not null references evm_token_transfer_grant(id) on delete restrict,
+    grant_id integer not null references evm_token_transfer_grant (id) on delete restrict,
-    log_id integer not null references evm_transaction_log(id) on delete restrict,
+    log_id integer not null references evm_transaction_log (id) on delete restrict,
     chain_id integer not null, -- EIP-155 chain ID
     token_contract blob not null, -- 20-byte ERC20 contract address
     recipient_address blob not null, -- 20-byte recipient address
     value blob not null, -- big-endian 32-byte U256
-    created_at integer not null default(unixepoch('now'))
+    created_at integer not null default(unixepoch ('now'))
 ) STRICT;
 
-create index if not exists idx_token_transfer_log_grant on evm_token_transfer_log(grant_id);
+create index if not exists idx_token_transfer_log_grant on evm_token_transfer_log (grant_id);
-create index if not exists idx_token_transfer_log_log_id on evm_token_transfer_log(log_id);
-create index if not exists idx_token_transfer_log_chain on evm_token_transfer_log(chain_id);
 
+create index if not exists idx_token_transfer_log_log_id on evm_token_transfer_log (log_id);
+
+create index if not exists idx_token_transfer_log_chain on evm_token_transfer_log (chain_id);
 
 -- ===============================
 -- Ether transfer grant (uses base log)
 -- ===============================
 create table if not exists evm_ether_transfer_grant (
     id integer not null primary key,
-    basic_grant_id integer not null unique references evm_basic_grant(id) on delete cascade,
+    basic_grant_id integer not null unique references evm_basic_grant (id) on delete cascade,
-    limit_id integer not null references evm_ether_transfer_limit(id) on delete restrict
+    limit_id integer not null references evm_ether_transfer_limit (id) on delete restrict
 ) STRICT;
 
 -- Specific recipient addresses for an ether transfer grant
 create table if not exists evm_ether_transfer_grant_target (
     id integer not null primary key,
-    grant_id integer not null references evm_ether_transfer_grant(id) on delete cascade,
+    grant_id integer not null references evm_ether_transfer_grant (id) on delete cascade,
     address blob not null -- 20-byte recipient address
 ) STRICT;
 
-create unique index if not exists uniq_ether_transfer_target on evm_ether_transfer_grant_target(grant_id, address);
+create unique index if not exists uniq_ether_transfer_target on evm_ether_transfer_grant_target (grant_id, address);
-

server/crates/arbiter-server/migrations/2026-03-15-103112-0000_add_program_client_pubkey_unique/down.sql

@@ -1 +0,0 @@
-DROP INDEX IF EXISTS program_client_public_key_unique;

server/crates/arbiter-server/migrations/2026-03-15-103112-0000_add_program_client_pubkey_unique/up.sql

@@ -1,2 +0,0 @@
-CREATE UNIQUE INDEX program_client_public_key_unique
-    ON program_client (public_key);

server/crates/arbiter-server/src/actors/bootstrap.rs

@@ -2,13 +2,8 @@ use arbiter_proto::{BOOTSTRAP_PATH, home_path};
 use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
 use kameo::{Actor, messages};
-use miette::Diagnostic;
+
-use rand::{
+use rand::{RngExt, distr::Alphanumeric, make_rng, rngs::StdRng};
-    RngExt,
-    distr::{Alphanumeric},
-    make_rng,
-    rngs::StdRng,
-};
 use thiserror::Error;
 
 use crate::db::{self, DatabasePool, schema};
@@ -30,18 +25,15 @@ pub async fn generate_token() -> Result<String, std::io::Error> {
     Ok(token)
 }
 
-#[derive(Error, Debug, Diagnostic)]
+#[derive(Error, Debug)]
 pub enum Error {
     #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter_server::bootstrap::database))]
     Database(#[from] db::PoolError),
 
     #[error("Database query error: {0}")]
-    #[diagnostic(code(arbiter_server::bootstrap::database_query))]
     Query(#[from] diesel::result::Error),
 
     #[error("I/O error: {0}")]
-    #[diagnostic(code(arbiter_server::bootstrap::io))]
     Io(#[from] std::io::Error),
 }
 
@@ -61,7 +53,6 @@ impl Bootstrapper {
 
         drop(conn);
 
-
         let token = if row_count == 0 {
             let token = generate_token().await?;
             Some(token)

server/crates/arbiter-server/src/actors/client/auth.rs

@@ -1,53 +1,81 @@
 use arbiter_proto::{
-    format_challenge,
+    ClientMetadata, format_challenge,
-    proto::client::{
+    transport::{Bi, expect_message},
-        AuthChallenge, AuthChallengeSolution, ClientConnectError, ClientRequest, ClientResponse,
+};
-        client_connect_error::Code as ConnectErrorCode,
+use chrono::Utc;
-        client_request::Payload as ClientRequestPayload,
+use diesel::{
-        client_response::Payload as ClientResponsePayload,
+    ExpressionMethods as _, OptionalExtension as _, QueryDsl as _, SelectableHelper as _,
-    },
+    dsl::insert_into, update,
-    transport::expect_message,
 };
-use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl as _, update};
 use diesel_async::RunQueryDsl as _;
-use ed25519_dalek::VerifyingKey;
+use ed25519_dalek::{Signature, VerifyingKey};
+use kameo::error::SendError;
 use tracing::error;
 
 use crate::{
-    actors::client::ClientConnection,
+    actors::{
-    db::{self, schema::program_client},
+        client::{ClientConnection, ClientProfile},
+        flow_coordinator::{self, RequestClientApproval},
+    },
+    db::{
+        self,
+        models::{ProgramClientMetadata, SqliteTimestamp},
+        schema::program_client,
+    },
 };
 
-use super::session::ClientSession;
-
 #[derive(thiserror::Error, Debug, Clone, PartialEq, Eq)]
 pub enum Error {
-    #[error("Unexpected message payload")]
-    UnexpectedMessagePayload,
-    #[error("Invalid client public key length")]
-    InvalidClientPubkeyLength,
-    #[error("Invalid client public key encoding")]
-    InvalidAuthPubkeyEncoding,
     #[error("Database pool unavailable")]
     DatabasePoolUnavailable,
     #[error("Database operation failed")]
     DatabaseOperationFailed,
     #[error("Invalid challenge solution")]
     InvalidChallengeSolution,
-    #[error("Client not registered")]
+    #[error("Client approval request failed")]
-    NotRegistered,
+    ApproveError(#[from] ApproveError),
-    #[error("Internal error")]
-    InternalError,
     #[error("Transport error")]
     Transport,
 }
 
+#[derive(thiserror::Error, Debug, Clone, PartialEq, Eq)]
+pub enum ApproveError {
+    #[error("Internal error")]
+    Internal,
+    #[error("Client connection denied by user agents")]
+    Denied,
+    #[error("Upstream error: {0}")]
+    Upstream(flow_coordinator::ApprovalError),
+}
+
+#[derive(Debug, Clone)]
+pub enum Inbound {
+    AuthChallengeRequest {
+        pubkey: VerifyingKey,
+        metadata: ClientMetadata,
+    },
+    AuthChallengeSolution {
+        signature: Signature,
+    },
+}
+
+#[derive(Debug, Clone)]
+pub enum Outbound {
+    AuthChallenge { pubkey: VerifyingKey, nonce: i32 },
+    AuthSuccess,
+}
+
+pub struct ClientInfo {
+    pub id: i32,
+    pub current_nonce: i32,
+}
+
 /// Atomically reads and increments the nonce for a known client.
 /// Returns `None` if the pubkey is not registered.
-async fn get_nonce(
+async fn get_client_and_nonce(
     db: &db::DatabasePool,
     pubkey: &VerifyingKey,
-) -> Result<Option<(i32, i32)>, Error> {
+) -> Result<Option<ClientInfo>, Error> {
     let pubkey_bytes = pubkey.as_bytes().to_vec();
 
     let mut conn = db.get().await.map_err(|e| {
@@ -56,7 +84,6 @@ async fn get_nonce(
     })?;
 
     conn.exclusive_transaction(|conn| {
-        let pubkey_bytes = pubkey_bytes.clone();
         Box::pin(async move {
             let Some((client_id, current_nonce)) = program_client::table
                 .filter(program_client::public_key.eq(&pubkey_bytes))
@@ -74,7 +101,10 @@ async fn get_nonce(
                 .execute(conn)
                 .await?;
 
-            Ok(Some((client_id, current_nonce)))
+            Ok(Some(ClientInfo {
+                id: client_id,
+                current_nonce,
+            }))
         })
     })
     .await
@@ -84,33 +114,162 @@ async fn get_nonce(
     })
 }
 
-async fn challenge_client(
+async fn approve_new_client(
-    props: &mut ClientConnection,
+    actors: &crate::actors::GlobalActors,
+    profile: ClientProfile,
+) -> Result<(), Error> {
+    let result = actors
+        .flow_coordinator
+        .ask(RequestClientApproval { client: profile })
+        .await;
+
+    match result {
+        Ok(true) => Ok(()),
+        Ok(false) => Err(Error::ApproveError(ApproveError::Denied)),
+        Err(SendError::HandlerError(e)) => {
+            error!(error = ?e, "Approval upstream error");
+            Err(Error::ApproveError(ApproveError::Upstream(e)))
+        }
+        Err(e) => {
+            error!(error = ?e, "Approval request to flow coordinator failed");
+            Err(Error::ApproveError(ApproveError::Internal))
+        }
+    }
+}
+
+async fn insert_client(
+    db: &db::DatabasePool,
+    pubkey: &VerifyingKey,
+    metadata: &ClientMetadata,
+) -> Result<i32, Error> {
+    use crate::db::schema::{client_metadata, program_client};
+    let mut conn = db.get().await.map_err(|e| {
+        error!(error = ?e, "Database pool error");
+        Error::DatabasePoolUnavailable
+    })?;
+
+    let metadata_id = insert_into(client_metadata::table)
+        .values((
+            client_metadata::name.eq(&metadata.name),
+            client_metadata::description.eq(&metadata.description),
+            client_metadata::version.eq(&metadata.version),
+        ))
+        .returning(client_metadata::id)
+        .get_result::<i32>(&mut conn)
+        .await
+        .map_err(|e| {
+            error!(error = ?e, "Failed to insert client metadata");
+            Error::DatabaseOperationFailed
+        })?;
+
+    let client_id = insert_into(program_client::table)
+        .values((
+            program_client::public_key.eq(pubkey.as_bytes().to_vec()),
+            program_client::metadata_id.eq(metadata_id),
+            program_client::nonce.eq(1), // pre-incremented; challenge uses 0
+        ))
+        .on_conflict_do_nothing()
+        .returning(program_client::id)
+        .get_result::<i32>(&mut conn)
+        .await
+        .map_err(|e| {
+            error!(error = ?e, "Failed to insert client metadata");
+            Error::DatabaseOperationFailed
+        })?;
+
+    Ok(client_id)
+}
+
+async fn sync_client_metadata(
+    db: &db::DatabasePool,
+    client_id: i32,
+    metadata: &ClientMetadata,
+) -> Result<(), Error> {
+    use crate::db::schema::{client_metadata, client_metadata_history};
+
+    let now = SqliteTimestamp(Utc::now());
+
+    let mut conn = db.get().await.map_err(|e| {
+        error!(error = ?e, "Database pool error");
+        Error::DatabasePoolUnavailable
+    })?;
+
+    conn.exclusive_transaction(|conn| {
+        let metadata = metadata.clone();
+        Box::pin(async move {
+            let (current_metadata_id, current): (i32, ProgramClientMetadata) =
+                program_client::table
+                    .find(client_id)
+                    .inner_join(client_metadata::table)
+                    .select((
+                        program_client::metadata_id,
+                        ProgramClientMetadata::as_select(),
+                    ))
+                    .first(conn)
+                    .await?;
+
+            let unchanged = current.name == metadata.name
+                && current.description == metadata.description
+                && current.version == metadata.version;
+            if unchanged {
+                return Ok(());
+            }
+
+            insert_into(client_metadata_history::table)
+                .values((
+                    client_metadata_history::metadata_id.eq(current_metadata_id),
+                    client_metadata_history::client_id.eq(client_id),
+                ))
+                .execute(conn)
+                .await?;
+
+            let metadata_id = insert_into(client_metadata::table)
+                .values((
+                    client_metadata::name.eq(&metadata.name),
+                    client_metadata::description.eq(&metadata.description),
+                    client_metadata::version.eq(&metadata.version),
+                ))
+                .returning(client_metadata::id)
+                .get_result::<i32>(conn)
+                .await?;
+
+            update(program_client::table.find(client_id))
+                .set((
+                    program_client::metadata_id.eq(metadata_id),
+                    program_client::updated_at.eq(now),
+                ))
+                .execute(conn)
+                .await?;
+
+            Ok::<(), diesel::result::Error>(())
+        })
+    })
+    .await
+    .map_err(|e| {
+        error!(error = ?e, "Database error");
+        Error::DatabaseOperationFailed
+    })
+}
+
+async fn challenge_client<T>(
+    transport: &mut T,
     pubkey: VerifyingKey,
     nonce: i32,
-) -> Result<(), Error> {
+) -> Result<(), Error>
-    let challenge = AuthChallenge {
+where
-        pubkey: pubkey.as_bytes().to_vec(),
+    T: Bi<Inbound, Result<Outbound, Error>> + ?Sized,
-        nonce,
+{
-    };
+    transport
-
+        .send(Ok(Outbound::AuthChallenge { pubkey, nonce }))
-    props
-        .transport
-        .send(Ok(ClientResponse {
-            payload: Some(ClientResponsePayload::AuthChallenge(challenge.clone())),
-        }))
         .await
         .map_err(|e| {
             error!(error = ?e, "Failed to send auth challenge");
             Error::Transport
         })?;
 
-    let AuthChallengeSolution { signature } =
+    let signature = expect_message(transport, |req: Inbound| match req {
-        expect_message(&mut *props.transport, |req: ClientRequest| {
+        Inbound::AuthChallengeSolution { signature } => Some(signature),
-            match req.payload? {
-                ClientRequestPayload::AuthChallengeSolution(s) => Some(s),
         _ => None,
-            }
     })
     .await
     .map_err(|e| {
@@ -118,13 +277,9 @@ async fn challenge_client(
         Error::Transport
     })?;
 
-    let formatted = format_challenge(nonce, &challenge.pubkey);
+    let formatted = format_challenge(nonce, pubkey.as_bytes());
-    let sig = signature.as_slice().try_into().map_err(|_| {
-        error!("Invalid signature length");
-        Error::InvalidChallengeSolution
-    })?;
 
-    pubkey.verify_strict(&formatted, &sig).map_err(|_| {
+    pubkey.verify_strict(&formatted, &signature).map_err(|_| {
         error!("Challenge solution verification failed");
         Error::InvalidChallengeSolution
     })?;
@@ -132,52 +287,43 @@ async fn challenge_client(
     Ok(())
 }
 
-fn connect_error_code(err: &Error) -> ConnectErrorCode {
+pub async fn authenticate<T>(props: &mut ClientConnection, transport: &mut T) -> Result<i32, Error>
-    match err {
+where
-        Error::NotRegistered => ConnectErrorCode::ApprovalDenied,
+    T: Bi<Inbound, Result<Outbound, Error>> + Send + ?Sized,
-        _ => ConnectErrorCode::Unknown,
+{
-    }
+    let Some(Inbound::AuthChallengeRequest { pubkey, metadata }) = transport.recv().await else {
-}
-
-async fn authenticate(props: &mut ClientConnection) -> Result<(VerifyingKey, i32), Error> {
-    let Some(ClientRequest {
-        payload: Some(ClientRequestPayload::AuthChallengeRequest(challenge)),
-    }) = props.transport.recv().await
-    else {
         return Err(Error::Transport);
     };
 
-    let pubkey_bytes = challenge
+    let info = match get_client_and_nonce(&props.db, &pubkey).await? {
-        .pubkey
+        Some(nonce) => nonce,
-        .as_array()
+        None => {
-        .ok_or(Error::InvalidClientPubkeyLength)?;
+            approve_new_client(
-    let pubkey =
+                &props.actors,
-        VerifyingKey::from_bytes(pubkey_bytes).map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
+                ClientProfile {
-
+                    pubkey,
-    let (client_id, nonce) = match get_nonce(&props.db, &pubkey).await? {
+                    metadata: metadata.clone(),
-        Some((client_id, nonce)) => (client_id, nonce),
+                },
-        None => return Err(Error::NotRegistered),
+            )
+            .await?;
+            let client_id = insert_client(&props.db, &pubkey, &metadata).await?;
+            ClientInfo {
+                id: client_id,
+                current_nonce: 0,
+            }
+        }
     };
 
-    challenge_client(props, pubkey, nonce).await?;
+    sync_client_metadata(&props.db, info.id, &metadata).await?;
+    challenge_client(transport, pubkey, info.current_nonce).await?;
 
-    Ok((pubkey, client_id))
+    transport
-}
+        .send(Ok(Outbound::AuthSuccess))
+        .await
+        .map_err(|e| {
+            error!(error = ?e, "Failed to send auth success");
+            Error::Transport
+        })?;
 
-pub async fn authenticate_and_create(mut props: ClientConnection) -> Result<ClientSession, Error> {
+    Ok(info.id)
-    match authenticate(&mut props).await {
-        Ok((_pubkey, client_id)) => Ok(ClientSession::new(props, client_id)),
-        Err(err) => {
-            let code = connect_error_code(&err);
-            let _ = props
-                .transport
-                .send(Ok(ClientResponse {
-                    payload: Some(ClientResponsePayload::ClientConnectError(
-                        ClientConnectError { code: code.into() },
-                    )),
-                }))
-                .await;
-            Err(err)
-        }
-    }
 }

server/crates/arbiter-server/src/actors/client/mod.rs

@@ -1,7 +1,4 @@
-use arbiter_proto::{
+use arbiter_proto::{ClientMetadata, transport::Bi};
-    proto::client::{ClientRequest, ClientResponse},
-    transport::Bi,
-};
 use kameo::actor::Spawn;
 use tracing::{error, info};
 
@@ -10,48 +7,37 @@ use crate::{
     db,
 };
 
-#[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
+#[derive(Debug, Clone)]
-pub enum ClientError {
+pub struct ClientProfile {
-    #[error("Expected message with payload")]
+    pub pubkey: ed25519_dalek::VerifyingKey,
-    MissingRequestPayload,
+    pub metadata: ClientMetadata,
-    #[error("Unexpected request payload")]
-    UnexpectedRequestPayload,
-    #[error("State machine error")]
-    StateTransitionFailed,
-    #[error("Connection registration failed")]
-    ConnectionRegistrationFailed,
-    #[error(transparent)]
-    Auth(#[from] auth::Error),
 }
 
-pub type Transport = Box<dyn Bi<ClientRequest, Result<ClientResponse, ClientError>> + Send>;
-
 pub struct ClientConnection {
     pub(crate) db: db::DatabasePool,
-    pub(crate) transport: Transport,
     pub(crate) actors: GlobalActors,
 }
 
 impl ClientConnection {
-    pub fn new(db: db::DatabasePool, transport: Transport, actors: GlobalActors) -> Self {
+    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
-        Self {
+        Self { db, actors }
-            db,
-            transport,
-            actors,
-        }
     }
 }
 
 pub mod auth;
 pub mod session;
 
-pub async fn connect_client(props: ClientConnection) {
+pub async fn connect_client<T>(mut props: ClientConnection, transport: &mut T)
-    match auth::authenticate_and_create(props).await {
+where
-        Ok(session) => {
+    T: Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> + Send + ?Sized,
-            ClientSession::spawn(session);
+{
+    match auth::authenticate(&mut props, transport).await {
+        Ok(client_id) => {
+            ClientSession::spawn(ClientSession::new(props, client_id));
             info!("Client authenticated, session started");
         }
         Err(err) => {
+            let _ = transport.send(Err(err.clone())).await;
             error!(?err, "Authentication failed, closing connection");
         }
     }

server/crates/arbiter-server/src/actors/client/session.rs

@@ -1,25 +1,18 @@
-use alloy::{consensus::TxEip1559, primitives::Address, rlp::Decodable};
+use kameo::{Actor, messages};
-use arbiter_proto::proto::{
+use tracing::error;
-    client::{
+
-        ClientRequest, ClientResponse, client_request::Payload as ClientRequestPayload,
+use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-        client_response::Payload as ClientResponsePayload,
-    },
-    evm::{
-        EvmError, EvmSignTransactionResponse, evm_sign_transaction_response::Result as SignResult,
-    },
-};
-use kameo::Actor;
-use tokio::select;
-use tracing::{error, info};
 
 use crate::{
     actors::{
         GlobalActors,
-        client::{ClientConnection, ClientError},
+        client::ClientConnection,
-        evm::ClientSignTransaction,
+        evm::{ClientSignTransaction, SignTransactionError},
-        router::RegisterClient,
+        flow_coordinator::RegisterClient,
+        keyholder::KeyHolderState,
     },
     db,
+    evm::VetError,
 };
 
 pub struct ClientSession {
@@ -31,62 +24,58 @@ impl ClientSession {
     pub(crate) fn new(props: ClientConnection, client_id: i32) -> Self {
         Self { props, client_id }
     }
+}
 
-    pub async fn process_transport_inbound(&mut self, req: ClientRequest) -> Output {
+#[messages]
-        let msg = req.payload.ok_or_else(|| {
+impl ClientSession {
-            error!(actor = "client", "Received message with no payload");
+    #[message]
-            ClientError::MissingRequestPayload
+    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<KeyHolderState, Error> {
-        })?;
+        use crate::actors::keyholder::GetState;
 
-        match msg {
+        let vault_state = match self.props.actors.key_holder.ask(GetState {}).await {
-            ClientRequestPayload::EvmSignTransaction(sign_req) => {
+            Ok(state) => state,
-                let wallet_address: [u8; 20] = sign_req
+            Err(err) => {
-                    .wallet_address
+                error!(?err, actor = "client", "keyholder.query.failed");
-                    .try_into()
+                return Err(Error::Internal);
-                    .map_err(|_| ClientError::UnexpectedRequestPayload)?;
+            }
+        };
 
-                let mut rlp_bytes: &[u8] = &sign_req.rlp_transaction;
+        Ok(vault_state)
-                let tx = TxEip1559::decode(&mut rlp_bytes)
+    }
-                    .map_err(|_| ClientError::UnexpectedRequestPayload)?;
 
-                let result = self
+    #[message]
+    pub(crate) async fn handle_sign_transaction(
+        &mut self,
+        wallet_address: Address,
+        transaction: TxEip1559,
+    ) -> Result<Signature, SignTransactionRpcError> {
+        match self
             .props
             .actors
             .evm
             .ask(ClientSignTransaction {
                 client_id: self.client_id,
-                        wallet_address: Address::from_slice(&wallet_address),
+                wallet_address,
-                        transaction: tx,
+                transaction,
             })
-                    .await;
+            .await
-
+        {
-                let response_result = match result {
+            Ok(signature) => Ok(signature),
-                    Ok(signature) => SignResult::Signature(signature.as_bytes().to_vec()),
+            Err(kameo::error::SendError::HandlerError(SignTransactionError::Vet(vet_error))) => {
+                Err(SignTransactionRpcError::Vet(vet_error))
+            }
             Err(err) => {
-                        error!(?err, "client sign transaction failed");
+                error!(?err, "Failed to sign EVM transaction in client session");
-                        SignResult::Error(EvmError::Internal.into())
+                Err(SignTransactionRpcError::Internal)
             }
-                };
-
-                Ok(ClientResponse {
-                    payload: Some(ClientResponsePayload::EvmSignTransaction(
-                        EvmSignTransactionResponse {
-                            result: Some(response_result),
-                        },
-                    )),
-                })
-            }
-            _ => Err(ClientError::UnexpectedRequestPayload),
         }
     }
 }
 
-type Output = Result<ClientResponse, ClientError>;
-
 impl Actor for ClientSession {
     type Args = Self;
 
-    type Error = ClientError;
+    type Error = Error;
 
     async fn on_start(
         args: Self::Args,
@@ -94,58 +83,37 @@ impl Actor for ClientSession {
     ) -> Result<Self, Self::Error> {
         args.props
             .actors
-            .router
+            .flow_coordinator
             .ask(RegisterClient { actor: this })
             .await
-            .map_err(|_| ClientError::ConnectionRegistrationFailed)?;
+            .map_err(|_| Error::ConnectionRegistrationFailed)?;
         Ok(args)
     }
-
-    async fn next(
-        &mut self,
-        _actor_ref: kameo::prelude::WeakActorRef<Self>,
-        mailbox_rx: &mut kameo::prelude::MailboxReceiver<Self>,
-    ) -> Option<kameo::mailbox::Signal<Self>> {
-        loop {
-            select! {
-                signal = mailbox_rx.recv() => {
-                    return signal;
-                }
-                msg = self.props.transport.recv() => {
-                    match msg {
-                        Some(request) => {
-                            match self.process_transport_inbound(request).await {
-                                Ok(resp) => {
-                                    if self.props.transport.send(Ok(resp)).await.is_err() {
-                                        error!(actor = "client", reason = "channel closed", "send.failed");
-                                        return Some(kameo::mailbox::Signal::Stop);
-                                    }
-                                }
-                                Err(err) => {
-                                    let _ = self.props.transport.send(Err(err)).await;
-                                    return Some(kameo::mailbox::Signal::Stop);
-                                }
-                            }
-                        }
-                        None => {
-                            info!(actor = "client", "transport.closed");
-                            return Some(kameo::mailbox::Signal::Stop);
-                        }
-                    }
-                }
-            }
-        }
-    }
 }
 
 impl ClientSession {
     pub fn new_test(db: db::DatabasePool, actors: GlobalActors) -> Self {
-        use arbiter_proto::transport::DummyTransport;
+        let props = ClientConnection::new(db, actors);
-        let transport: super::Transport = Box::new(DummyTransport::new());
-        let props = ClientConnection::new(db, transport, actors);
         Self {
             props,
             client_id: 0,
         }
     }
 }
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Connection registration failed")]
+    ConnectionRegistrationFailed,
+    #[error("Internal error")]
+    Internal,
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum SignTransactionRpcError {
+    #[error("Policy evaluation failed")]
+    Vet(#[from] VetError),
+
+    #[error("Internal error")]
+    Internal,
+}

server/crates/arbiter-server/src/actors/evm/mod.rs

@@ -1,77 +1,61 @@
 use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
-use diesel::{ExpressionMethods, OptionalExtension as _, QueryDsl, SelectableHelper as _, dsl::insert_into};
+use diesel::{
+    ExpressionMethods, OptionalExtension as _, QueryDsl, SelectableHelper as _, dsl::insert_into,
+};
 use diesel_async::RunQueryDsl;
 use kameo::{Actor, actor::ActorRef, messages};
-use memsafe::MemSafe;
 use rand::{SeedableRng, rng, rngs::StdRng};
 
 use crate::{
     actors::keyholder::{CreateNew, Decrypt, KeyHolder},
-    db::{self, DatabasePool, models::{self, EvmBasicGrant, SqliteTimestamp}, schema},
+    db::{
+        DatabaseError, DatabasePool,
+        models::{self, SqliteTimestamp},
+        schema,
+    },
     evm::{
         self, RunKind,
         policies::{
-            FullGrant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
+            FullGrant, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
-            ether_transfer::EtherTransfer,
+            ether_transfer::EtherTransfer, token_transfers::TokenTransfer,
-            token_transfers::TokenTransfer,
         },
     },
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 
 pub use crate::evm::safe_signer;
 
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
+#[derive(Debug, thiserror::Error)]
 pub enum SignTransactionError {
     #[error("Wallet not found")]
-    #[diagnostic(code(arbiter::evm::sign::wallet_not_found))]
     WalletNotFound,
 
     #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::database))]
+    Database(#[from] DatabaseError),
-    Database(#[from] diesel::result::Error),
-
-    #[error("Database pool error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::pool))]
-    Pool(#[from] db::PoolError),
 
     #[error("Keyholder error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::keyholder))]
     Keyholder(#[from] crate::actors::keyholder::Error),
 
     #[error("Keyholder mailbox error")]
-    #[diagnostic(code(arbiter::evm::sign::keyholder_send))]
     KeyholderSend,
 
     #[error("Signing error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::signing))]
     Signing(#[from] alloy::signers::Error),
 
     #[error("Policy error: {0}")]
-    #[diagnostic(code(arbiter::evm::sign::vet))]
     Vet(#[from] evm::VetError),
 }
 
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
+#[derive(Debug, thiserror::Error)]
 pub enum Error {
     #[error("Keyholder error: {0}")]
-    #[diagnostic(code(arbiter::evm::keyholder))]
     Keyholder(#[from] crate::actors::keyholder::Error),
 
     #[error("Keyholder mailbox error")]
-    #[diagnostic(code(arbiter::evm::keyholder_send))]
     KeyholderSend,
 
     #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter::evm::database))]
+    Database(#[from] DatabaseError),
-    Database(#[from] diesel::result::Error),
-
-    #[error("Database pool error: {0}")]
-    #[diagnostic(code(arbiter::evm::database_pool))]
-    DatabasePool(#[from] db::PoolError),
-
-    #[error("Grant creation error: {0}")]
-    #[diagnostic(code(arbiter::evm::creation))]
-    Creation(#[from] evm::CreationError),
 }
 
 #[derive(Actor)]
@@ -88,21 +72,22 @@ impl EvmActor {
         // todo: audit
         let rng = StdRng::from_rng(&mut rng());
         let engine = evm::Engine::new(db.clone());
-        Self { keyholder, db, rng, engine }
+        Self {
+            keyholder,
+            db,
+            rng,
+            engine,
+        }
     }
 }
 
 #[messages]
 impl EvmActor {
     #[message]
-    pub async fn generate(&mut self) -> Result<Address, Error> {
+    pub async fn generate(&mut self) -> Result<(i32, Address), Error> {
         let (mut key_cell, address) = safe_signer::generate(&mut self.rng);
 
-        // Move raw key bytes into a Vec<u8> MemSafe for KeyHolder
+        let plaintext = key_cell.read_inline(|reader| SafeCell::new(reader.to_vec()));
-        let plaintext = {
-            let reader = key_cell.read().expect("MemSafe read");
-            MemSafe::new(reader.to_vec()).expect("MemSafe allocation")
-        };
 
         let aead_id: i32 = self
             .keyholder
@@ -110,29 +95,32 @@ impl EvmActor {
             .await
             .map_err(|_| Error::KeyholderSend)?;
 
-        let mut conn = self.db.get().await?;
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
-        insert_into(schema::evm_wallet::table)
+        let wallet_id = insert_into(schema::evm_wallet::table)
             .values(&models::NewEvmWallet {
                 address: address.as_slice().to_vec(),
                 aead_encrypted_id: aead_id,
             })
-            .execute(&mut conn)
+            .returning(schema::evm_wallet::id)
-            .await?;
+            .get_result(&mut conn)
+            .await
+            .map_err(DatabaseError::from)?;
 
-        Ok(address)
+        Ok((wallet_id, address))
     }
 
     #[message]
-    pub async fn list_wallets(&self) -> Result<Vec<Address>, Error> {
+    pub async fn list_wallets(&self) -> Result<Vec<(i32, Address)>, Error> {
-        let mut conn = self.db.get().await?;
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
         let rows: Vec<models::EvmWallet> = schema::evm_wallet::table
             .select(models::EvmWallet::as_select())
             .load(&mut conn)
-            .await?;
+            .await
+            .map_err(DatabaseError::from)?;
 
         Ok(rows
             .into_iter()
-            .map(|w| Address::from_slice(&w.address))
+            .map(|w| (w.id, Address::from_slice(&w.address)))
             .collect())
     }
 }
@@ -142,19 +130,24 @@ impl EvmActor {
     #[message]
     pub async fn useragent_create_grant(
         &mut self,
-        client_id: i32,
         basic: SharedGrantSettings,
         grant: SpecificGrant,
-    ) -> Result<i32, evm::CreationError> {
+    ) -> Result<i32, DatabaseError> {
         match grant {
             SpecificGrant::EtherTransfer(settings) => {
                 self.engine
-                    .create_grant::<EtherTransfer>(client_id, FullGrant { basic, specific: settings })
+                    .create_grant::<EtherTransfer>(FullGrant {
+                        basic,
+                        specific: settings,
+                    })
                     .await
             }
             SpecificGrant::TokenTransfer(settings) => {
                 self.engine
-                    .create_grant::<TokenTransfer>(client_id, FullGrant { basic, specific: settings })
+                    .create_grant::<TokenTransfer>(FullGrant {
+                        basic,
+                        specific: settings,
+                    })
                     .await
             }
         }
@@ -162,29 +155,23 @@ impl EvmActor {
 
     #[message]
     pub async fn useragent_delete_grant(&mut self, grant_id: i32) -> Result<(), Error> {
-        let mut conn = self.db.get().await?;
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
         diesel::update(schema::evm_basic_grant::table)
             .filter(schema::evm_basic_grant::id.eq(grant_id))
             .set(schema::evm_basic_grant::revoked_at.eq(SqliteTimestamp::now()))
             .execute(&mut conn)
-            .await?;
+            .await
+            .map_err(DatabaseError::from)?;
         Ok(())
     }
 
     #[message]
-    pub async fn useragent_list_grants(
+    pub async fn useragent_list_grants(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
-        &mut self,
+        Ok(self
-        wallet_id: Option<i32>,
+            .engine
-    ) -> Result<Vec<EvmBasicGrant>, Error> {
+            .list_all_grants()
-        let mut conn = self.db.get().await?;
+            .await
-        let mut query = schema::evm_basic_grant::table
+            .map_err(DatabaseError::from)?)
-            .select(EvmBasicGrant::as_select())
-            .filter(schema::evm_basic_grant::revoked_at.is_null())
-            .into_boxed();
-        if let Some(wid) = wallet_id {
-            query = query.filter(schema::evm_basic_grant::wallet_id.eq(wid));
-        }
-        Ok(query.load(&mut conn).await?)
     }
 
     #[message]
@@ -194,18 +181,29 @@ impl EvmActor {
         wallet_address: Address,
         transaction: TxEip1559,
     ) -> Result<SpecificMeaning, SignTransactionError> {
-        let mut conn = self.db.get().await?;
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
         let wallet = schema::evm_wallet::table
             .select(models::EvmWallet::as_select())
             .filter(schema::evm_wallet::address.eq(wallet_address.as_slice()))
             .first(&mut conn)
             .await
-            .optional()?
+            .optional()
+            .map_err(DatabaseError::from)?
+            .ok_or(SignTransactionError::WalletNotFound)?;
+        let wallet_access = schema::evm_wallet_access::table
+            .select(models::EvmWalletAccess::as_select())
+            .filter(schema::evm_wallet_access::wallet_id.eq(wallet.id))
+            .filter(schema::evm_wallet_access::client_id.eq(client_id))
+            .first(&mut conn)
+            .await
+            .optional()
+            .map_err(DatabaseError::from)?
             .ok_or(SignTransactionError::WalletNotFound)?;
         drop(conn);
 
-        let meaning = self.engine
+        let meaning = self
-            .evaluate_transaction(wallet.id, client_id, transaction.clone(), RunKind::Execution)
+            .engine
+            .evaluate_transaction(wallet_access, transaction.clone(), RunKind::Execution)
             .await?;
 
         Ok(meaning)
@@ -218,26 +216,38 @@ impl EvmActor {
         wallet_address: Address,
         mut transaction: TxEip1559,
     ) -> Result<Signature, SignTransactionError> {
-        let mut conn = self.db.get().await?;
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
         let wallet = schema::evm_wallet::table
             .select(models::EvmWallet::as_select())
             .filter(schema::evm_wallet::address.eq(wallet_address.as_slice()))
             .first(&mut conn)
             .await
-            .optional()?
+            .optional()
+            .map_err(DatabaseError::from)?
+            .ok_or(SignTransactionError::WalletNotFound)?;
+        let wallet_access = schema::evm_wallet_access::table
+            .select(models::EvmWalletAccess::as_select())
+            .filter(schema::evm_wallet_access::wallet_id.eq(wallet.id))
+            .filter(schema::evm_wallet_access::client_id.eq(client_id))
+            .first(&mut conn)
+            .await
+            .optional()
+            .map_err(DatabaseError::from)?
             .ok_or(SignTransactionError::WalletNotFound)?;
         drop(conn);
 
-        let raw_key: MemSafe<Vec<u8>> = self
+        let raw_key: SafeCell<Vec<u8>> = self
             .keyholder
-            .ask(Decrypt { aead_id: wallet.aead_encrypted_id })
+            .ask(Decrypt {
+                aead_id: wallet.aead_encrypted_id,
+            })
             .await
             .map_err(|_| SignTransactionError::KeyholderSend)?;
 
-        let signer = safe_signer::SafeSigner::from_memsafe(raw_key)?;
+        let signer = safe_signer::SafeSigner::from_cell(raw_key)?;
 
         self.engine
-            .evaluate_transaction(wallet.id, client_id, transaction.clone(), RunKind::Execution)
+            .evaluate_transaction(wallet_access, transaction.clone(), RunKind::Execution)
             .await?;
 
         use alloy::network::TxSignerSync as _;

server/crates/arbiter-server/src/actors/flow_coordinator/client_connect_approval.rs

@@ -0,0 +1,105 @@
+use std::ops::ControlFlow;
+
+use kameo::{
+    Actor, messages,
+    prelude::{ActorId, ActorRef, ActorStopReason, Context, WeakActorRef},
+    reply::ReplySender,
+};
+
+use crate::actors::{
+    client::ClientProfile,
+    flow_coordinator::ApprovalError,
+    user_agent::{UserAgentSession, session::BeginNewClientApproval},
+};
+
+pub struct Args {
+    pub client: ClientProfile,
+    pub user_agents: Vec<ActorRef<UserAgentSession>>,
+    pub reply: ReplySender<Result<bool, ApprovalError>>,
+}
+
+pub struct ClientApprovalController {
+    /// Number of UAs that have not yet responded (approval or denial) or died.
+    pending: usize,
+    /// Number of approvals received so far.
+    approved: usize,
+    reply: Option<ReplySender<Result<bool, ApprovalError>>>,
+}
+
+impl ClientApprovalController {
+    fn send_reply(&mut self, result: Result<bool, ApprovalError>) {
+        if let Some(reply) = self.reply.take() {
+            reply.send(result);
+        }
+    }
+}
+
+impl Actor for ClientApprovalController {
+    type Args = Args;
+    type Error = ();
+
+    async fn on_start(
+        Args {
+            client,
+            mut user_agents,
+            reply,
+        }: Self::Args,
+        actor_ref: ActorRef<Self>,
+    ) -> Result<Self, Self::Error> {
+        let this = Self {
+            pending: user_agents.len(),
+            approved: 0,
+            reply: Some(reply),
+        };
+
+        for user_agent in user_agents.drain(..) {
+            actor_ref.link(&user_agent).await;
+            let _ = user_agent
+                .tell(BeginNewClientApproval {
+                    client: client.clone(),
+                    controller: actor_ref.clone(),
+                })
+                .await;
+        }
+
+        Ok(this)
+    }
+
+    async fn on_link_died(
+        &mut self,
+        _: WeakActorRef<Self>,
+        _: ActorId,
+        _: ActorStopReason,
+    ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
+        // A linked UA died before responding — counts as a non-approval.
+        self.pending = self.pending.saturating_sub(1);
+        if self.pending == 0 {
+            // At least one UA didn't approve: deny.
+            self.send_reply(Ok(false));
+            return Ok(ControlFlow::Break(ActorStopReason::Normal));
+        }
+        Ok(ControlFlow::Continue(()))
+    }
+}
+
+#[messages]
+impl ClientApprovalController {
+    #[message(ctx)]
+    pub async fn client_approval_answer(&mut self, approved: bool, ctx: &mut Context<Self, ()>) {
+        if !approved {
+            // Denial wins immediately regardless of other pending responses.
+            self.send_reply(Ok(false));
+            ctx.stop();
+            return;
+        }
+
+        self.approved += 1;
+        self.pending = self.pending.saturating_sub(1);
+
+        if self.pending == 0 {
+            // Every connected UA approved.
+            self.send_reply(Ok(true));
+            ctx.stop();
+        }
+    }
+}

server/crates/arbiter-server/src/actors/flow_coordinator/mod.rs

@@ -0,0 +1,118 @@
+use std::{collections::HashMap, ops::ControlFlow};
+
+use kameo::{
+    Actor,
+    actor::{ActorId, ActorRef, Spawn},
+    messages,
+    prelude::{ActorStopReason, Context, WeakActorRef},
+    reply::DelegatedReply,
+};
+use tracing::info;
+
+use crate::actors::{
+    client::{ClientProfile, session::ClientSession},
+    flow_coordinator::client_connect_approval::ClientApprovalController,
+    user_agent::session::UserAgentSession,
+};
+
+pub mod client_connect_approval;
+
+#[derive(Default)]
+pub struct FlowCoordinator {
+    pub user_agents: HashMap<ActorId, ActorRef<UserAgentSession>>,
+    pub clients: HashMap<ActorId, ActorRef<ClientSession>>,
+}
+
+impl Actor for FlowCoordinator {
+    type Args = Self;
+
+    type Error = ();
+
+    async fn on_start(args: Self::Args, _: ActorRef<Self>) -> Result<Self, Self::Error> {
+        Ok(args)
+    }
+
+    async fn on_link_died(
+        &mut self,
+        _: WeakActorRef<Self>,
+        id: ActorId,
+        _: ActorStopReason,
+    ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
+        if self.user_agents.remove(&id).is_some() {
+            info!(
+                ?id,
+                actor = "FlowCoordinator",
+                event = "useragent.disconnected"
+            );
+        } else if self.clients.remove(&id).is_some() {
+            info!(
+                ?id,
+                actor = "FlowCoordinator",
+                event = "client.disconnected"
+            );
+        } else {
+            info!(
+                ?id,
+                actor = "FlowCoordinator",
+                event = "unknown.actor.disconnected"
+            );
+        }
+        Ok(ControlFlow::Continue(()))
+    }
+}
+
+#[derive(Debug, thiserror::Error, Clone, PartialEq, Eq, Hash)]
+pub enum ApprovalError {
+    #[error("No user agents connected")]
+    NoUserAgentsConnected,
+}
+
+#[messages]
+impl FlowCoordinator {
+    #[message(ctx)]
+    pub async fn register_user_agent(
+        &mut self,
+        actor: ActorRef<UserAgentSession>,
+        ctx: &mut Context<Self, ()>,
+    ) {
+        info!(id = %actor.id(), actor = "FlowCoordinator", event = "useragent.connected");
+        ctx.actor_ref().link(&actor).await;
+        self.user_agents.insert(actor.id(), actor);
+    }
+
+    #[message(ctx)]
+    pub async fn register_client(
+        &mut self,
+        actor: ActorRef<ClientSession>,
+        ctx: &mut Context<Self, ()>,
+    ) {
+        info!(id = %actor.id(), actor = "FlowCoordinator", event = "client.connected");
+        ctx.actor_ref().link(&actor).await;
+        self.clients.insert(actor.id(), actor);
+    }
+
+    #[message(ctx)]
+    pub async fn request_client_approval(
+        &mut self,
+        client: ClientProfile,
+        ctx: &mut Context<Self, DelegatedReply<Result<bool, ApprovalError>>>,
+    ) -> DelegatedReply<Result<bool, ApprovalError>> {
+        let (reply, Some(reply_sender)) = ctx.reply_sender() else {
+            unreachable!("Expected `request_client_approval` to have callback channel");
+        };
+
+        let refs: Vec<_> = self.user_agents.values().cloned().collect();
+        if refs.is_empty() {
+            reply_sender.send(Err(ApprovalError::NoUserAgentsConnected));
+            return reply;
+        }
+
+        ClientApprovalController::spawn(client_connect_approval::Args {
+            client,
+            user_agents: refs,
+            reply: reply_sender,
+        });
+
+        reply
+    }
+}

server/crates/arbiter-server/src/actors/keyholder/encryption/v1.rs

@@ -1,237 +0,0 @@
-use std::ops::Deref as _;
-
-use argon2::{Algorithm, Argon2, password_hash::Salt as ArgonSalt};
-use chacha20poly1305::{
-    AeadInPlace, Key, KeyInit as _, XChaCha20Poly1305, XNonce,
-    aead::{AeadMut, Error, Payload},
-};
-use memsafe::MemSafe;
-use rand::{
-    Rng as _, SeedableRng,
-    rngs::{StdRng, SysRng},
-};
-
-pub const ROOT_KEY_TAG: &[u8] = "arbiter/seal/v1".as_bytes();
-pub const TAG: &[u8] = "arbiter/private-key/v1".as_bytes();
-
-pub const NONCE_LENGTH: usize = 24;
-
-#[derive(Default)]
-pub struct Nonce([u8; NONCE_LENGTH]);
-impl Nonce {
-    pub fn increment(&mut self) {
-        for i in (0..self.0.len()).rev() {
-            if self.0[i] == 0xFF {
-                self.0[i] = 0;
-            } else {
-                self.0[i] += 1;
-                break;
-            }
-        }
-    }
-
-    pub fn to_vec(&self) -> Vec<u8> {
-        self.0.to_vec()
-    }
-}
-impl<'a> TryFrom<&'a [u8]> for Nonce {
-    type Error = ();
-
-    fn try_from(value: &'a [u8]) -> Result<Self, Self::Error> {
-        if value.len() != NONCE_LENGTH {
-            return Err(());
-        }
-        let mut nonce = [0u8; NONCE_LENGTH];
-        nonce.copy_from_slice(value);
-        Ok(Self(nonce))
-    }
-}
-
-pub struct KeyCell(pub MemSafe<Key>);
-impl From<MemSafe<Key>> for KeyCell {
-    fn from(value: MemSafe<Key>) -> Self {
-        Self(value)
-    }
-}
-impl TryFrom<MemSafe<Vec<u8>>> for KeyCell {
-    type Error = ();
-
-    fn try_from(mut value: MemSafe<Vec<u8>>) -> Result<Self, Self::Error> {
-        let value = value.read().unwrap();
-        if value.len() != size_of::<Key>() {
-            return Err(());
-        }
-        let mut cell = MemSafe::new(Key::default()).unwrap();
-        {
-            let mut cell_write = cell.write().unwrap();
-            let cell_slice: &mut [u8] = cell_write.as_mut();
-            cell_slice.copy_from_slice(&value);
-        }
-        Ok(Self(cell))
-    }
-}
-
-impl KeyCell {
-    pub fn new_secure_random() -> Self {
-        let mut key = MemSafe::new(Key::default()).unwrap();
-        {
-            let mut key_buffer = key.write().unwrap();
-            let key_buffer: &mut [u8] = key_buffer.as_mut();
-
-            let mut rng = StdRng::try_from_rng(&mut SysRng).unwrap();
-            rng.fill_bytes(key_buffer);
-        }
-
-        key.into()
-    }
-
-    pub fn encrypt_in_place(
-        &mut self,
-        nonce: &Nonce,
-        associated_data: &[u8],
-        mut buffer: impl AsMut<Vec<u8>>,
-    ) -> Result<(), Error> {
-        let key_reader = self.0.read().unwrap();
-        let key_ref = key_reader.deref();
-        let cipher = XChaCha20Poly1305::new(key_ref);
-        let nonce = XNonce::from_slice(nonce.0.as_ref());
-        let buffer = buffer.as_mut();
-        cipher.encrypt_in_place(nonce, associated_data, buffer)
-    }
-    pub fn decrypt_in_place(
-        &mut self,
-        nonce: &Nonce,
-        associated_data: &[u8],
-        buffer: &mut MemSafe<Vec<u8>>,
-    ) -> Result<(), Error> {
-        let key_reader = self.0.read().unwrap();
-        let key_ref = key_reader.deref();
-        let cipher = XChaCha20Poly1305::new(key_ref);
-        let nonce = XNonce::from_slice(nonce.0.as_ref());
-        let mut buffer = buffer.write().unwrap();
-        let buffer: &mut Vec<u8> = buffer.as_mut();
-        cipher.decrypt_in_place(nonce, associated_data, buffer)
-    }
-
-    pub fn encrypt(
-        &mut self,
-        nonce: &Nonce,
-        associated_data: &[u8],
-        plaintext: impl AsRef<[u8]>,
-    ) -> Result<Vec<u8>, Error> {
-        let key_reader = self.0.read().unwrap();
-        let key_ref = key_reader.deref();
-        let mut cipher = XChaCha20Poly1305::new(key_ref);
-        let nonce = XNonce::from_slice(nonce.0.as_ref());
-
-        let ciphertext = cipher.encrypt(
-            nonce,
-            Payload {
-                msg: plaintext.as_ref(),
-                aad: associated_data,
-            },
-        )?;
-        Ok(ciphertext)
-    }
-}
-
-pub type Salt = [u8; ArgonSalt::RECOMMENDED_LENGTH];
-
-pub fn generate_salt() -> Salt {
-    let mut salt = Salt::default();
-    let mut rng = StdRng::try_from_rng(&mut SysRng).unwrap();
-    rng.fill_bytes(&mut salt);
-    salt
-}
-
-/// User password might be of different length, have not enough entropy, etc...
-/// Derive a fixed-length key from the password using Argon2id, which is designed for password hashing and key derivation.
-pub fn derive_seal_key(mut password: MemSafe<Vec<u8>>, salt: &Salt) -> KeyCell {
-    let params = argon2::Params::new(262_144, 3, 4, None).unwrap();
-    let hasher = Argon2::new(Algorithm::Argon2id, argon2::Version::V0x13, params);
-    let mut key = MemSafe::new(Key::default()).unwrap();
-    {
-        let password_source = password.read().unwrap();
-        let mut key_buffer = key.write().unwrap();
-        let key_buffer: &mut [u8] = key_buffer.as_mut();
-
-        hasher
-            .hash_password_into(password_source.deref(), salt, key_buffer)
-            .unwrap();
-    }
-
-    key.into()
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use memsafe::MemSafe;
-
-    #[test]
-    pub fn derive_seal_key_deterministic() {
-        static PASSWORD: &[u8] = b"password";
-        let password = MemSafe::new(PASSWORD.to_vec()).unwrap();
-        let password2 = MemSafe::new(PASSWORD.to_vec()).unwrap();
-        let salt = generate_salt();
-
-        let mut key1 = derive_seal_key(password, &salt);
-        let mut key2 = derive_seal_key(password2, &salt);
-
-        let key1_reader = key1.0.read().unwrap();
-        let key2_reader = key2.0.read().unwrap();
-
-        assert_eq!(key1_reader.deref(), key2_reader.deref());
-    }
-
-    #[test]
-    pub fn successful_derive() {
-        static PASSWORD: &[u8] = b"password";
-        let password = MemSafe::new(PASSWORD.to_vec()).unwrap();
-        let salt = generate_salt();
-
-        let mut key = derive_seal_key(password, &salt);
-        let key_reader = key.0.read().unwrap();
-        let key_ref = key_reader.deref();
-
-        assert_ne!(key_ref.as_slice(), &[0u8; 32][..]);
-    }
-
-    #[test]
-    pub fn encrypt_decrypt() {
-        static PASSWORD: &[u8] = b"password";
-        let password = MemSafe::new(PASSWORD.to_vec()).unwrap();
-        let salt = generate_salt();
-
-        let mut key = derive_seal_key(password, &salt);
-        let nonce = Nonce(*b"unique nonce 123 1231233"); // 24 bytes for XChaCha20Poly1305
-        let associated_data = b"associated data";
-        let mut buffer = b"secret data".to_vec();
-
-        key.encrypt_in_place(&nonce, associated_data, &mut buffer)
-            .unwrap();
-        assert_ne!(buffer, b"secret data");
-
-        let mut buffer = MemSafe::new(buffer).unwrap();
-
-        key.decrypt_in_place(&nonce, associated_data, &mut buffer)
-            .unwrap();
-
-        let buffer = buffer.read().unwrap();
-        assert_eq!(*buffer, b"secret data");
-    }
-
-    #[test]
-    // We should fuzz this
-    pub fn test_nonce_increment() {
-        let mut nonce = Nonce([0u8; NONCE_LENGTH]);
-        nonce.increment();
-
-        assert_eq!(
-            nonce.0,
-            [
-                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
-            ]
-        );
-    }
-}

server/crates/arbiter-server/src/actors/keyholder/mod.rs

@@ -5,21 +5,28 @@ use diesel::{
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
 use kameo::{Actor, Reply, messages};
-use memsafe::MemSafe;
 use strum::{EnumDiscriminants, IntoDiscriminant};
 use tracing::{error, info};
 
-use crate::db::{
+use crate::{
+    crypto::{
+        KeyCell, derive_key,
+        encryption::v1::{self, Nonce},
+        integrity::v1::compute_integrity_tag,
+    },
+    safe_cell::SafeCell,
+};
+use crate::{
+    db::{
         self,
         models::{self, RootKeyHistory},
         schema::{self},
+    },
+    safe_cell::SafeCellHandle as _,
 };
-use encryption::v1::{self, KeyCell, Nonce};
-
-pub mod encryption;
 
 #[derive(Default, EnumDiscriminants)]
-#[strum_discriminants(derive(Reply), vis(pub))]
+#[strum_discriminants(derive(Reply), vis(pub), name(KeyHolderState))]
 enum State {
     #[default]
     Unbootstrapped,
@@ -32,36 +39,28 @@ enum State {
     },
 }
 
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
+#[derive(Debug, thiserror::Error)]
 pub enum Error {
     #[error("Keyholder is already bootstrapped")]
-    #[diagnostic(code(arbiter::keyholder::already_bootstrapped))]
     AlreadyBootstrapped,
     #[error("Keyholder is not bootstrapped")]
-    #[diagnostic(code(arbiter::keyholder::not_bootstrapped))]
     NotBootstrapped,
     #[error("Invalid key provided")]
-    #[diagnostic(code(arbiter::keyholder::invalid_key))]
     InvalidKey,
 
     #[error("Requested aead entry not found")]
-    #[diagnostic(code(arbiter::keyholder::aead_not_found))]
     NotFound,
 
     #[error("Encryption error: {0}")]
-    #[diagnostic(code(arbiter::keyholder::encryption_error))]
     Encryption(#[from] chacha20poly1305::aead::Error),
 
     #[error("Database error: {0}")]
-    #[diagnostic(code(arbiter::keyholder::database_error))]
     DatabaseConnection(#[from] db::PoolError),
 
     #[error("Database transaction error: {0}")]
-    #[diagnostic(code(arbiter::keyholder::database_transaction_error))]
     DatabaseTransaction(#[from] diesel::result::Error),
 
     #[error("Broken database")]
-    #[diagnostic(code(arbiter::keyholder::broken_database))]
     BrokenDatabase,
 }
 
@@ -111,8 +110,7 @@ impl KeyHolder {
                         .first(conn)
                         .await?;
 
-                    let mut nonce =
+                    let mut nonce = Nonce::try_from(current_nonce.as_slice()).map_err(|_| {
-                        v1::Nonce::try_from(current_nonce.as_slice()).map_err(|_| {
                         error!(
                             "Broken database: invalid nonce for root key history id={}",
                             root_key_id
@@ -136,28 +134,27 @@ impl KeyHolder {
     }
 
     #[message]
-    pub async fn bootstrap(&mut self, seal_key_raw: MemSafe<Vec<u8>>) -> Result<(), Error> {
+    pub async fn bootstrap(&mut self, seal_key_raw: SafeCell<Vec<u8>>) -> Result<(), Error> {
         if !matches!(self.state, State::Unbootstrapped) {
             return Err(Error::AlreadyBootstrapped);
         }
         let salt = v1::generate_salt();
-        let mut seal_key = v1::derive_seal_key(seal_key_raw, &salt);
+        let mut seal_key = derive_key(seal_key_raw, &salt);
         let mut root_key = KeyCell::new_secure_random();
 
         // Zero nonces are fine because they are one-time
-        let root_key_nonce = v1::Nonce::default();
+        let root_key_nonce = Nonce::default();
-        let data_encryption_nonce = v1::Nonce::default();
+        let data_encryption_nonce = Nonce::default();
 
-        let root_key_ciphertext: Vec<u8> = {
+        let root_key_ciphertext: Vec<u8> = root_key.0.read_inline(|reader| {
-            let root_key_reader = root_key.0.read().unwrap();
+            let root_key_reader = reader.as_slice();
-            let root_key_reader = root_key_reader.as_slice();
             seal_key
                 .encrypt(&root_key_nonce, v1::ROOT_KEY_TAG, root_key_reader)
                 .map_err(|err| {
                     error!(?err, "Fatal bootstrap error");
                     Error::Encryption(err)
-                })?
+                })
-        };
+        })?;
 
         let mut conn = self.db.get().await?;
 
@@ -199,7 +196,7 @@ impl KeyHolder {
     }
 
     #[message]
-    pub async fn try_unseal(&mut self, seal_key_raw: MemSafe<Vec<u8>>) -> Result<(), Error> {
+    pub async fn try_unseal(&mut self, seal_key_raw: SafeCell<Vec<u8>>) -> Result<(), Error> {
         let State::Sealed {
             root_key_history_id,
         } = &self.state
@@ -212,7 +209,6 @@ impl KeyHolder {
             let mut conn = self.db.get().await?;
             schema::root_key_history::table
                 .filter(schema::root_key_history::id.eq(*root_key_history_id))
-                .select(schema::root_key_history::data_encryption_nonce)
                 .select(RootKeyHistory::as_select())
                 .first(&mut conn)
                 .await?
@@ -223,9 +219,9 @@ impl KeyHolder {
             error!("Broken database: invalid salt for root key");
             Error::BrokenDatabase
         })?;
-        let mut seal_key = v1::derive_seal_key(seal_key_raw, &salt);
+        let mut seal_key = derive_key(seal_key_raw, &salt);
 
-        let mut root_key = MemSafe::new(current_key.ciphertext.clone()).unwrap();
+        let mut root_key = SafeCell::new(current_key.ciphertext.clone());
 
         let nonce = v1::Nonce::try_from(current_key.root_key_encryption_nonce.as_slice()).map_err(
             |_| {
@@ -243,7 +239,7 @@ impl KeyHolder {
 
         self.state = State::Unsealed {
             root_key_history_id: current_key.id,
-            root_key: v1::KeyCell::try_from(root_key).map_err(|err| {
+            root_key: KeyCell::try_from(root_key).map_err(|err| {
                 error!(?err, "Broken database: invalid encryption key size");
                 Error::BrokenDatabase
             })?,
@@ -254,9 +250,24 @@ impl KeyHolder {
         Ok(())
     }
 
-    // Decrypts the `aead_encrypted` entry with the given ID and returns the plaintext
+    // Signs a generic integrity payload using the vault-derived integrity key
     #[message]
-    pub async fn decrypt(&mut self, aead_id: i32) -> Result<MemSafe<Vec<u8>>, Error> {
+    pub fn sign_integrity_tag(
+        &mut self,
+        purpose_tag: Vec<u8>,
+        data_parts: Vec<Vec<u8>>,
+    ) -> Result<Vec<u8>, Error> {
+        let State::Unsealed { root_key, .. } = &mut self.state else {
+            return Err(Error::NotBootstrapped);
+        };
+
+        let tag =
+            compute_integrity_tag(root_key, &purpose_tag, data_parts.iter().map(Vec::as_slice));
+        Ok(tag.to_vec())
+    }
+
+    #[message]
+    pub async fn decrypt(&mut self, aead_id: i32) -> Result<SafeCell<Vec<u8>>, Error> {
         let State::Unsealed { root_key, .. } = &mut self.state else {
             return Err(Error::NotBootstrapped);
         };
@@ -279,17 +290,18 @@ impl KeyHolder {
             );
             Error::BrokenDatabase
         })?;
-        let mut output = MemSafe::new(row.ciphertext).unwrap();
+        let mut output = SafeCell::new(row.ciphertext);
         root_key.decrypt_in_place(&nonce, v1::TAG, &mut output)?;
         Ok(output)
     }
 
     // Creates new `aead_encrypted` entry in the database and returns it's ID
     #[message]
-    pub async fn create_new(&mut self, mut plaintext: MemSafe<Vec<u8>>) -> Result<i32, Error> {
+    pub async fn create_new(&mut self, mut plaintext: SafeCell<Vec<u8>>) -> Result<i32, Error> {
         let State::Unsealed {
             root_key,
             root_key_history_id,
+            ..
         } = &mut self.state
         else {
             return Err(Error::NotBootstrapped);
@@ -299,7 +311,7 @@ impl KeyHolder {
         // Borrow checker note: &mut borrow a few lines above is disjoint from this field
         let nonce = Self::get_new_nonce(&self.db, *root_key_history_id).await?;
 
-        let mut ciphertext_buffer = plaintext.write().unwrap();
+        let mut ciphertext_buffer = plaintext.write();
         let ciphertext_buffer: &mut Vec<u8> = ciphertext_buffer.as_mut();
         root_key.encrypt_in_place(&nonce, v1::TAG, &mut *ciphertext_buffer)?;
 
@@ -313,7 +325,7 @@ impl KeyHolder {
                 current_nonce: nonce.to_vec(),
                 schema_version: 1,
                 associated_root_key_id: *root_key_history_id,
-                created_at: Utc::now().into()
+                created_at: Utc::now().into(),
             })
             .returning(schema::aead_encrypted::id)
             .get_result(&mut conn)
@@ -323,7 +335,7 @@ impl KeyHolder {
     }
 
     #[message]
-    pub fn get_state(&self) -> StateDiscriminants {
+    pub fn get_state(&self) -> KeyHolderState {
         self.state.discriminant()
     }
 
@@ -348,15 +360,17 @@ mod tests {
     use diesel::SelectableHelper;
 
     use diesel_async::RunQueryDsl;
-    use memsafe::MemSafe;
 
-    use crate::db::{self};
+    use crate::{
+        db::{self},
+        safe_cell::SafeCell,
+    };
 
     use super::*;
 
     async fn bootstrapped_actor(db: &db::DatabasePool) -> KeyHolder {
         let mut actor = KeyHolder::new(db.clone()).await.unwrap();
-        let seal_key = MemSafe::new(b"test-seal-key".to_vec()).unwrap();
+        let seal_key = SafeCell::new(b"test-seal-key".to_vec());
         actor.bootstrap(seal_key).await.unwrap();
         actor
     }
@@ -391,7 +405,7 @@ mod tests {
         assert_eq!(root_row.data_encryption_nonce, n2.to_vec());
 
         let id = actor
-            .create_new(MemSafe::new(b"post-interleave".to_vec()).unwrap())
+            .create_new(SafeCell::new(b"post-interleave".to_vec()))
             .await
             .unwrap();
         let row: models::AeadEncrypted = schema::aead_encrypted::table

server/crates/arbiter-server/src/actors/mod.rs

@@ -1,27 +1,27 @@
 use kameo::actor::{ActorRef, Spawn};
-use miette::Diagnostic;
 use thiserror::Error;
 
 use crate::{
-    actors::{bootstrap::Bootstrapper, evm::EvmActor, keyholder::KeyHolder, router::MessageRouter},
+    actors::{
+        bootstrap::Bootstrapper, evm::EvmActor, flow_coordinator::FlowCoordinator,
+        keyholder::KeyHolder,
+    },
     db,
 };
 
 pub mod bootstrap;
 pub mod client;
 mod evm;
+pub mod flow_coordinator;
 pub mod keyholder;
-pub mod router;
 pub mod user_agent;
 
-#[derive(Error, Debug, Diagnostic)]
+#[derive(Error, Debug)]
 pub enum SpawnError {
     #[error("Failed to spawn Bootstrapper actor")]
-    #[diagnostic(code(SpawnError::Bootstrapper))]
     Bootstrapper(#[from] bootstrap::Error),
 
     #[error("Failed to spawn KeyHolder actor")]
-    #[diagnostic(code(SpawnError::KeyHolder))]
     KeyHolder(#[from] keyholder::Error),
 }
 
@@ -30,7 +30,7 @@ pub enum SpawnError {
 pub struct GlobalActors {
     pub key_holder: ActorRef<KeyHolder>,
     pub bootstrapper: ActorRef<Bootstrapper>,
-    pub router: ActorRef<MessageRouter>,
+    pub flow_coordinator: ActorRef<FlowCoordinator>,
     pub evm: ActorRef<EvmActor>,
 }
 
@@ -41,7 +41,7 @@ impl GlobalActors {
             bootstrapper: Bootstrapper::spawn(Bootstrapper::new(&db).await?),
             evm: EvmActor::spawn(EvmActor::new(key_holder.clone(), db)),
             key_holder,
-            router: MessageRouter::spawn(MessageRouter::default()),
+            flow_coordinator: FlowCoordinator::spawn(FlowCoordinator::default()),
         })
     }
 }

server/crates/arbiter-server/src/actors/router/mod.rs

@@ -1,76 +0,0 @@
-use std::{collections::HashMap, ops::ControlFlow};
-
-use kameo::{
-    Actor,
-    actor::{ActorId, ActorRef},
-    messages,
-    prelude::{ActorStopReason, Context, WeakActorRef},
-};
-use tracing::info;
-
-use crate::actors::{client::session::ClientSession, user_agent::session::UserAgentSession};
-
-#[derive(Default)]
-pub struct MessageRouter {
-    pub user_agents: HashMap<ActorId, ActorRef<UserAgentSession>>,
-    pub clients: HashMap<ActorId, ActorRef<ClientSession>>,
-}
-
-impl Actor for MessageRouter {
-    type Args = Self;
-
-    type Error = ();
-
-    async fn on_start(args: Self::Args, _: ActorRef<Self>) -> Result<Self, Self::Error> {
-        Ok(args)
-    }
-
-    async fn on_link_died(
-        &mut self,
-        _: WeakActorRef<Self>,
-        id: ActorId,
-        _: ActorStopReason,
-    ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
-        if self.user_agents.remove(&id).is_some() {
-            info!(
-                ?id,
-                actor = "MessageRouter",
-                event = "useragent.disconnected"
-            );
-        } else if self.clients.remove(&id).is_some() {
-            info!(?id, actor = "MessageRouter", event = "client.disconnected");
-        } else {
-            info!(
-                ?id,
-                actor = "MessageRouter",
-                event = "unknown.actor.disconnected"
-            );
-        }
-        Ok(ControlFlow::Continue(()))
-    }
-}
-
-#[messages]
-impl MessageRouter {
-    #[message(ctx)]
-    pub async fn register_user_agent(
-        &mut self,
-        actor: ActorRef<UserAgentSession>,
-        ctx: &mut Context<Self, ()>,
-    ) {
-        info!(id = %actor.id(), actor = "MessageRouter", event = "useragent.connected");
-        ctx.actor_ref().link(&actor).await;
-        self.user_agents.insert(actor.id(), actor);
-    }
-
-    #[message(ctx)]
-    pub async fn register_client(
-        &mut self,
-        actor: ActorRef<ClientSession>,
-        ctx: &mut Context<Self, ()>,
-    ) {
-        info!(id = %actor.id(), actor = "MessageRouter", event = "client.connected");
-        ctx.actor_ref().link(&actor).await;
-        self.clients.insert(actor.id(), actor);
-    }
-}

server/crates/arbiter-server/src/actors/user_agent/auth.rs

@@ -1,114 +1,82 @@
-use arbiter_proto::proto::user_agent::{
+use arbiter_proto::transport::Bi;
-    AuthChallengeRequest, AuthChallengeSolution, KeyType as ProtoKeyType, UserAgentRequest,
-    user_agent_request::Payload as UserAgentRequestPayload,
-};
 use tracing::error;
 
 use crate::actors::user_agent::{
-    UserAgentConnection,
+    AuthPublicKey, UserAgentConnection,
-    auth::state::{AuthContext, AuthPublicKey, AuthStateMachine},
+    auth::state::{AuthContext, AuthStateMachine},
-    session::UserAgentSession,
 };
 
-#[derive(thiserror::Error, Debug, PartialEq)]
-pub enum Error {
-    #[error("Unexpected message payload")]
-    UnexpectedMessagePayload,
-    #[error("Invalid client public key length")]
-    InvalidClientPubkeyLength,
-    #[error("Invalid client public key encoding")]
-    InvalidAuthPubkeyEncoding,
-    #[error("Database pool unavailable")]
-    DatabasePoolUnavailable,
-    #[error("Database operation failed")]
-    DatabaseOperationFailed,
-    #[error("Public key not registered")]
-    PublicKeyNotRegistered,
-    #[error("Transport error")]
-    Transport,
-    #[error("Invalid bootstrap token")]
-    InvalidBootstrapToken,
-    #[error("Bootstrapper actor unreachable")]
-    BootstrapperActorUnreachable,
-    #[error("Invalid challenge solution")]
-    InvalidChallengeSolution,
-}
-
 mod state;
 use state::*;
 
-fn parse_pubkey(key_type: ProtoKeyType, pubkey: Vec<u8>) -> Result<AuthPublicKey, Error> {
+#[derive(Debug, Clone)]
-    match key_type {
+pub enum Inbound {
-        // UNSPECIFIED treated as Ed25519 for backward compatibility
+    AuthChallengeRequest {
-        ProtoKeyType::Unspecified | ProtoKeyType::Ed25519 => {
+        pubkey: AuthPublicKey,
-            let pubkey_bytes = pubkey.as_array().ok_or(Error::InvalidClientPubkeyLength)?;
+        bootstrap_token: Option<String>,
-            let key = ed25519_dalek::VerifyingKey::from_bytes(pubkey_bytes)
+    },
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
+    AuthChallengeSolution {
-            Ok(AuthPublicKey::Ed25519(key))
+        signature: Vec<u8>,
-        }
+    },
-        ProtoKeyType::EcdsaSecp256k1 => {
+}
-            // Public key is sent as 33-byte SEC1 compressed point
+
-            let key = k256::ecdsa::VerifyingKey::from_sec1_bytes(&pubkey)
+#[derive(Debug)]
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
+pub enum Error {
-            Ok(AuthPublicKey::EcdsaSecp256k1(key))
+    UnregisteredPublicKey,
-        }
+    InvalidChallengeSolution,
-        ProtoKeyType::Rsa => {
+    InvalidBootstrapToken,
-            use rsa::pkcs8::DecodePublicKey as _;
+    Internal { details: String },
-            let key = rsa::RsaPublicKey::from_public_key_der(&pubkey)
+    Transport,
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
+}
-            Ok(AuthPublicKey::Rsa(key))
+
+impl Error {
+    fn internal(details: impl Into<String>) -> Self {
+        Self::Internal {
+            details: details.into(),
         }
     }
 }
 
-fn parse_auth_event(payload: UserAgentRequestPayload) -> Result<AuthEvents, Error> {
+#[derive(Debug, Clone)]
+pub enum Outbound {
+    AuthChallenge { nonce: i32 },
+    AuthSuccess,
+}
+
+fn parse_auth_event(payload: Inbound) -> AuthEvents {
     match payload {
-        UserAgentRequestPayload::AuthChallengeRequest(AuthChallengeRequest {
+        Inbound::AuthChallengeRequest {
             pubkey,
             bootstrap_token: None,
-            key_type,
+        } => AuthEvents::AuthRequest(ChallengeRequest { pubkey }),
-        }) => {
+        Inbound::AuthChallengeRequest {
-            let kt = ProtoKeyType::try_from(key_type).unwrap_or(ProtoKeyType::Unspecified);
-            Ok(AuthEvents::AuthRequest(ChallengeRequest {
-                pubkey: parse_pubkey(kt, pubkey)?,
-            }))
-        }
-        UserAgentRequestPayload::AuthChallengeRequest(AuthChallengeRequest {
             pubkey,
             bootstrap_token: Some(token),
-            key_type,
+        } => AuthEvents::BootstrapAuthRequest(BootstrapAuthRequest { pubkey, token }),
-        }) => {
+        Inbound::AuthChallengeSolution { signature } => {
-            let kt = ProtoKeyType::try_from(key_type).unwrap_or(ProtoKeyType::Unspecified);
+            AuthEvents::ReceivedSolution(ChallengeSolution {
-            Ok(AuthEvents::BootstrapAuthRequest(BootstrapAuthRequest {
-                pubkey: parse_pubkey(kt, pubkey)?,
-                token,
-            }))
-        }
-        UserAgentRequestPayload::AuthChallengeSolution(AuthChallengeSolution { signature }) => {
-            Ok(AuthEvents::ReceivedSolution(ChallengeSolution {
                 solution: signature,
-            }))
+            })
         }
-        _ => Err(Error::UnexpectedMessagePayload),
     }
 }
 
-pub async fn authenticate(props: &mut UserAgentConnection) -> Result<AuthPublicKey, Error> {
+pub async fn authenticate<T>(
-    let mut state = AuthStateMachine::new(AuthContext::new(props));
+    props: &mut UserAgentConnection,
+    transport: T,
+) -> Result<AuthPublicKey, Error>
+where
+    T: Bi<Inbound, Result<Outbound, Error>> + Send,
+{
+    let mut state = AuthStateMachine::new(AuthContext::new(props, transport));
 
     loop {
         // `state` holds a mutable reference to `props` so we can't access it directly here
-        let transport = state.context_mut().conn.transport.as_mut();
+        let Some(payload) = state.context_mut().transport.recv().await else {
-        let Some(UserAgentRequest {
-            payload: Some(payload),
-        }) = transport.recv().await
-        else {
             return Err(Error::Transport);
         };
 
-        let event = parse_auth_event(payload)?;
+        match state.process_event(parse_auth_event(payload)).await {
-
-        match state.process_event(event).await {
             Ok(AuthStates::AuthOk(key)) => return Ok(key.clone()),
             Err(AuthError::ActionFailed(err)) => {
                 error!(?err, "State machine action failed");
@@ -131,11 +99,3 @@ pub async fn authenticate(props: &mut UserAgentConnection) -> Result<AuthPublicK
         }
     }
 }
-
-pub async fn authenticate_and_create(
-    mut props: UserAgentConnection,
-) -> Result<UserAgentSession, Error> {
-    let _key = authenticate(&mut props).await?;
-    let session = UserAgentSession::new(props);
-    Ok(session)
-}

server/crates/arbiter-server/src/actors/user_agent/auth/state.rs

@@ -1,50 +1,25 @@
-use arbiter_proto::proto::user_agent::{
+use arbiter_proto::transport::Bi;
-    AuthChallenge, UserAgentResponse, user_agent_response::Payload as UserAgentResponsePayload,
-};
 use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, update};
 use diesel_async::RunQueryDsl;
+use kameo::error::SendError;
 use tracing::error;
 
 use super::Error;
 use crate::{
-    actors::{bootstrap::ConsumeToken, user_agent::UserAgentConnection},
+    actors::{
-    db::{models::KeyType, schema},
+        bootstrap::ConsumeToken,
+        keyholder::{self, SignIntegrityTag},
+        user_agent::{AuthPublicKey, UserAgentConnection, auth::Outbound},
+    },
+    crypto::integrity::v1::USERAGENT_INTEGRITY_TAG,
+    db::schema,
 };
 
-/// Abstraction over Ed25519 / ECDSA-secp256k1 / RSA public keys used during the auth handshake.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[derive(Clone)]
+pub enum AttestationStatus {
-pub enum AuthPublicKey {
+    Attested,
-    Ed25519(ed25519_dalek::VerifyingKey),
+    NotAttested,
-    /// Compressed SEC1 public key; signature bytes are raw 64-byte (r||s).
+    Unavailable,
-    EcdsaSecp256k1(k256::ecdsa::VerifyingKey),
-    /// RSA-2048+ public key (Windows Hello / KeyCredentialManager); signature bytes are PSS+SHA-256.
-    Rsa(rsa::RsaPublicKey),
-}
-
-impl AuthPublicKey {
-    /// Canonical bytes stored in DB and echoed back in the challenge.
-    /// Ed25519: raw 32 bytes. ECDSA: SEC1 compressed 33 bytes. RSA: DER-encoded SPKI.
-    pub fn to_stored_bytes(&self) -> Vec<u8> {
-        match self {
-            AuthPublicKey::Ed25519(k) => k.to_bytes().to_vec(),
-            // SEC1 compressed (33 bytes) is the natural compact format for secp256k1
-            AuthPublicKey::EcdsaSecp256k1(k) => k.to_encoded_point(true).as_bytes().to_vec(),
-            AuthPublicKey::Rsa(k) => {
-                use rsa::pkcs8::EncodePublicKey as _;
-                k.to_public_key_der()
-                    .expect("rsa SPKI encoding is infallible")
-                    .to_vec()
-            }
-        }
-    }
-
-    pub fn key_type(&self) -> KeyType {
-        match self {
-            AuthPublicKey::Ed25519(_) => KeyType::Ed25519,
-            AuthPublicKey::EcdsaSecp256k1(_) => KeyType::EcdsaSecp256k1,
-            AuthPublicKey::Rsa(_) => KeyType::Rsa,
-        }
-    }
 }
 
 pub struct ChallengeRequest {
@@ -57,7 +32,7 @@ pub struct BootstrapAuthRequest {
 }
 
 pub struct ChallengeContext {
-    pub challenge: AuthChallenge,
+    pub challenge_nonce: i32,
     pub key: AuthPublicKey,
 }
 
@@ -70,27 +45,33 @@ smlang::statemachine!(
     custom_error: true,
     transitions: {
         *Init + AuthRequest(ChallengeRequest) / async prepare_challenge = SentChallenge(ChallengeContext),
-        Init + BootstrapAuthRequest(BootstrapAuthRequest) [async verify_bootstrap_token] / provide_key_bootstrap = AuthOk(AuthPublicKey),
+        Init + BootstrapAuthRequest(BootstrapAuthRequest) / async verify_bootstrap_token = AuthOk(AuthPublicKey),
-        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) [async verify_solution] / provide_key = AuthOk(AuthPublicKey),
+        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) / async verify_solution = AuthOk(AuthPublicKey),
     }
 );
 
-async fn create_nonce(db: &crate::db::DatabasePool, pubkey_bytes: &[u8]) -> Result<i32, Error> {
+async fn create_nonce(
+    db: &crate::db::DatabasePool,
+    pubkey_bytes: &[u8],
+    key_type: crate::db::models::KeyType,
+) -> Result<i32, Error> {
     let mut db_conn = db.get().await.map_err(|e| {
         error!(error = ?e, "Database pool error");
-        Error::DatabasePoolUnavailable
+        Error::internal("Database unavailable")
     })?;
     db_conn
         .exclusive_transaction(|conn| {
             Box::pin(async move {
                 let current_nonce = schema::useragent_client::table
                     .filter(schema::useragent_client::public_key.eq(pubkey_bytes.to_vec()))
+                    .filter(schema::useragent_client::key_type.eq(key_type))
                     .select(schema::useragent_client::nonce)
                     .first::<i32>(conn)
                     .await?;
 
                 update(schema::useragent_client::table)
                     .filter(schema::useragent_client::public_key.eq(pubkey_bytes.to_vec()))
+                    .filter(schema::useragent_client::key_type.eq(key_type))
                     .set(schema::useragent_client::nonce.eq(current_nonce + 1))
                     .execute(conn)
                     .await?;
@@ -102,20 +83,24 @@ async fn create_nonce(db: &crate::db::DatabasePool, pubkey_bytes: &[u8]) -> Resu
         .optional()
         .map_err(|e| {
             error!(error = ?e, "Database error");
-            Error::DatabaseOperationFailed
+            Error::internal("Database operation failed")
         })?
         .ok_or_else(|| {
             error!(?pubkey_bytes, "Public key not found in database");
-            Error::PublicKeyNotRegistered
+            Error::UnregisteredPublicKey
         })
 }
 
-async fn register_key(db: &crate::db::DatabasePool, pubkey: &AuthPublicKey) -> Result<(), Error> {
+async fn register_key(
+    db: &crate::db::DatabasePool,
+    pubkey: &AuthPublicKey,
+    integrity_tag: Option<Vec<u8>>,
+) -> Result<(), Error> {
     let pubkey_bytes = pubkey.to_stored_bytes();
     let key_type = pubkey.key_type();
     let mut conn = db.get().await.map_err(|e| {
         error!(error = ?e, "Database pool error");
-        Error::DatabasePoolUnavailable
+        Error::internal("Database unavailable")
     })?;
 
     diesel::insert_into(schema::useragent_client::table)
@@ -123,36 +108,116 @@ async fn register_key(db: &crate::db::DatabasePool, pubkey: &AuthPublicKey) -> R
             schema::useragent_client::public_key.eq(pubkey_bytes),
             schema::useragent_client::nonce.eq(1),
             schema::useragent_client::key_type.eq(key_type),
+            schema::useragent_client::pubkey_integrity_tag.eq(integrity_tag),
         ))
         .execute(&mut conn)
         .await
         .map_err(|e| {
             error!(error = ?e, "Database error");
-            Error::DatabaseOperationFailed
+            Error::internal("Database operation failed")
         })?;
 
     Ok(())
 }
 
-pub struct AuthContext<'a> {
+pub struct AuthContext<'a, T> {
     pub(super) conn: &'a mut UserAgentConnection,
+    pub(super) transport: T,
 }
 
-impl<'a> AuthContext<'a> {
+impl<'a, T> AuthContext<'a, T> {
-    pub fn new(conn: &'a mut UserAgentConnection) -> Self {
+    pub fn new(conn: &'a mut UserAgentConnection, transport: T) -> Self {
-        Self { conn }
+        Self { conn, transport }
     }
 }
 
-impl AuthStateMachineContext for AuthContext<'_> {
+impl<T> AuthStateMachineContext for AuthContext<'_, T>
+where
+    T: Bi<super::Inbound, Result<super::Outbound, Error>> + Send,
+{
     type Error = Error;
 
+    async fn prepare_challenge(
+        &mut self,
+        ChallengeRequest { pubkey }: ChallengeRequest,
+    ) -> Result<ChallengeContext, Self::Error> {
+        match self.verify_pubkey_attestation_status(&pubkey).await? {
+            AttestationStatus::Attested | AttestationStatus::Unavailable => {}
+            AttestationStatus::NotAttested => {
+                return Err(Error::InvalidChallengeSolution);
+            }
+        }
+
+        let stored_bytes = pubkey.to_stored_bytes();
+        let nonce = create_nonce(&self.conn.db, &stored_bytes, pubkey.key_type()).await?;
+
+        self.transport
+            .send(Ok(Outbound::AuthChallenge { nonce }))
+            .await
+            .map_err(|e| {
+                error!(?e, "Failed to send auth challenge");
+                Error::Transport
+            })?;
+
+        Ok(ChallengeContext {
+            challenge_nonce: nonce,
+            key: pubkey,
+        })
+    }
+
+    #[allow(missing_docs)]
+    #[allow(clippy::result_unit_err)]
+    async fn verify_bootstrap_token(
+        &mut self,
+        BootstrapAuthRequest { pubkey, token }: BootstrapAuthRequest,
+    ) -> Result<AuthPublicKey, Self::Error> {
+        let token_ok: bool = self
+            .conn
+            .actors
+            .bootstrapper
+            .ask(ConsumeToken {
+                token: token.clone(),
+            })
+            .await
+            .map_err(|e| {
+                error!(?e, "Failed to consume bootstrap token");
+                Error::internal("Failed to consume bootstrap token")
+            })?;
+
+        if !token_ok {
+            error!("Invalid bootstrap token provided");
+            return Err(Error::InvalidBootstrapToken);
+        }
+
+        let integrity_tag = self
+            .try_sign_pubkey_integrity_tag(&pubkey)
+            .await
+            .map_err(|err| {
+                error!(?err, "Failed to sign user-agent pubkey integrity tag");
+                Error::internal("Failed to sign user-agent pubkey integrity tag")
+            })?;
+
+        register_key(&self.conn.db, &pubkey, integrity_tag).await?;
+
+        self.transport
+            .send(Ok(Outbound::AuthSuccess))
+            .await
+            .map_err(|_| Error::Transport)?;
+
+        Ok(pubkey)
+    }
+
+    #[allow(missing_docs)]
+    #[allow(clippy::unused_unit)]
     async fn verify_solution(
-        &self,
+        &mut self,
-        ChallengeContext { challenge, key }: &ChallengeContext,
+        ChallengeContext {
-        ChallengeSolution { solution }: &ChallengeSolution,
+            challenge_nonce,
-    ) -> Result<bool, Self::Error> {
+            key,
-        let formatted = arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
+        }: &ChallengeContext,
+        ChallengeSolution { solution }: ChallengeSolution,
+    ) -> Result<AuthPublicKey, Self::Error> {
+        let formatted = arbiter_proto::format_challenge(*challenge_nonce, &key.to_stored_bytes());
 
         let valid = match key {
             AuthPublicKey::Ed25519(vk) => {
@@ -181,117 +246,111 @@ impl AuthStateMachineContext for AuthContext<'_> {
             }
         };
 
-        Ok(valid)
+        match valid {
-    }
+            true => {
-
+                self.transport
-    async fn prepare_challenge(
+                    .send(Ok(Outbound::AuthSuccess))
-        &mut self,
-        ChallengeRequest { pubkey }: ChallengeRequest,
-    ) -> Result<ChallengeContext, Self::Error> {
-        let stored_bytes = pubkey.to_stored_bytes();
-        let nonce = create_nonce(&self.conn.db, &stored_bytes).await?;
-
-        let challenge = AuthChallenge {
-            pubkey: stored_bytes,
-            nonce,
-        };
-
-        self.conn
-            .transport
-            .send(Ok(UserAgentResponse {
-                payload: Some(UserAgentResponsePayload::AuthChallenge(challenge.clone())),
-            }))
                     .await
-            .map_err(|e| {
+                    .map_err(|_| Error::Transport)?;
-                error!(?e, "Failed to send auth challenge");
+                Ok(key.clone())
-                Error::Transport
-            })?;
-
-        Ok(ChallengeContext {
-            challenge,
-            key: pubkey,
-        })
             }
-
+            false => {
-    #[allow(missing_docs)]
+                self.transport
-    #[allow(clippy::result_unit_err)]
+                    .send(Err(Error::InvalidChallengeSolution))
-    async fn verify_bootstrap_token(
-        &self,
-        BootstrapAuthRequest { pubkey, token }: &BootstrapAuthRequest,
-    ) -> Result<bool, Self::Error> {
-        let token_ok: bool = self
-            .conn
-            .actors
-            .bootstrapper
-            .ask(ConsumeToken {
-                token: token.clone(),
-            })
                     .await
-            .map_err(|e| {
+                    .map_err(|_| Error::Transport)?;
-                error!(?e, "Failed to consume bootstrap token");
+                Err(Error::InvalidChallengeSolution)
-                Error::BootstrapperActorUnreachable
+            }
-            })?;
+        }
-
+    }
-        if !token_ok {
+}
-            error!("Invalid bootstrap token provided");
+
-            return Err(Error::InvalidBootstrapToken);
+impl<T> AuthContext<'_, T>
+where
+    T: Bi<super::Inbound, Result<super::Outbound, Error>> + Send,
+{
+    async fn try_sign_pubkey_integrity_tag(
+        &self,
+        pubkey: &AuthPublicKey,
+    ) -> Result<Option<Vec<u8>>, Error> {
+        let signed = self
+            .conn
+            .actors
+            .key_holder
+            .ask(SignIntegrityTag {
+                purpose_tag: USERAGENT_INTEGRITY_TAG.to_vec(),
+                data_parts: vec![
+                    (pubkey.key_type() as i32).to_be_bytes().to_vec(),
+                    pubkey.to_stored_bytes(),
+                ],
+            })
+            .await;
+
+        match signed {
+            Ok(tag) => Ok(Some(tag)),
+            Err(SendError::HandlerError(keyholder::Error::NotBootstrapped)) => Ok(None),
+            Err(SendError::HandlerError(err)) => {
+                error!(
+                    ?err,
+                    "Keyholder failed to sign user-agent pubkey integrity tag"
+                );
+                Err(Error::internal(
+                    "Keyholder failed to sign user-agent pubkey integrity tag",
+                ))
+            }
+            Err(err) => {
+                error!(
+                    ?err,
+                    "Failed to contact keyholder for user-agent pubkey integrity tag"
+                );
+                Err(Error::internal(
+                    "Failed to contact keyholder for user-agent pubkey integrity tag",
+                ))
+            }
+        }
+    }
+
+    async fn verify_pubkey_attestation_status(
+        &self,
+        pubkey: &AuthPublicKey,
+    ) -> Result<AttestationStatus, Error> {
+        let stored_tag: Option<Option<Vec<u8>>> = {
+            let mut conn = self.conn.db.get().await.map_err(|e| {
+                error!(error = ?e, "Database pool error");
+                Error::internal("Database unavailable")
+            })?;
+
+            schema::useragent_client::table
+                .filter(schema::useragent_client::public_key.eq(pubkey.to_stored_bytes()))
+                .filter(schema::useragent_client::key_type.eq(pubkey.key_type()))
+                .select(schema::useragent_client::pubkey_integrity_tag)
+                .first::<Option<Vec<u8>>>(&mut conn)
+                .await
+                .optional()
+                .map_err(|e| {
+                    error!(error = ?e, "Database error");
+                    Error::internal("Database operation failed")
+                })?
+        };
+
+        let Some(stored_tag) = stored_tag else {
+            return Err(Error::UnregisteredPublicKey);
+        };
+
+        let Some(expected_tag) = self.try_sign_pubkey_integrity_tag(pubkey).await? else {
+            return Ok(AttestationStatus::Unavailable);
+        };
+
+        match stored_tag {
+            Some(stored_tag) if stored_tag == expected_tag => Ok(AttestationStatus::Attested),
+            Some(_) => {
+                error!("User-agent pubkey integrity tag mismatch");
+                Ok(AttestationStatus::NotAttested)
+            }
+            None => {
+                error!("Missing pubkey integrity tag for registered key while vault is unsealed");
+                Ok(AttestationStatus::NotAttested)
             }
-
-        register_key(&self.conn.db, pubkey).await?;
-
-        Ok(true)
         }
-
-    fn provide_key_bootstrap(
-        &mut self,
-        event_data: BootstrapAuthRequest,
-    ) -> Result<AuthPublicKey, Self::Error> {
-        Ok(event_data.pubkey)
-    }
-
-    fn provide_key(
-        &mut self,
-        state_data: &ChallengeContext,
-        _: ChallengeSolution,
-    ) -> Result<AuthPublicKey, Self::Error> {
-        // ChallengeContext.key cannot be taken by value because smlang passes it by ref;
-        // we reconstruct stored bytes and return them wrapped in Ed25519 placeholder.
-        // Session uses only the raw bytes, so we carry them via a Vec<u8>.
-        // IMPORTANT: do NOT simplify this by storing the key type separately — the
-        // `AuthPublicKey` enum IS the source of truth for key bytes and type.
-        //
-        // smlang state-machine trait requires returning an owned value from `provide_key`,
-        // but `state_data` is only available by shared reference here.  We extract the
-        // stored bytes and re-wrap as the correct variant so the caller can call
-        // `to_stored_bytes()` / `key_type()` without losing information.
-        let bytes = state_data.challenge.pubkey.clone();
-        let key_type = state_data.key.key_type();
-        let rebuilt = match key_type {
-            crate::db::models::KeyType::Ed25519 => {
-                let arr: &[u8; 32] = bytes
-                    .as_slice()
-                    .try_into()
-                    .expect("ed25519 pubkey must be 32 bytes in challenge");
-                AuthPublicKey::Ed25519(
-                    ed25519_dalek::VerifyingKey::from_bytes(arr)
-                        .expect("key was already validated in parse_auth_event"),
-                )
-            }
-            crate::db::models::KeyType::EcdsaSecp256k1 => {
-                // bytes are SEC1 compressed (33 bytes produced by to_encoded_point(true))
-                AuthPublicKey::EcdsaSecp256k1(
-                    k256::ecdsa::VerifyingKey::from_sec1_bytes(&bytes)
-                        .expect("ecdsa key was already validated in parse_auth_event"),
-                )
-            }
-            crate::db::models::KeyType::Rsa => {
-                use rsa::pkcs8::DecodePublicKey as _;
-                AuthPublicKey::Rsa(
-                    rsa::RsaPublicKey::from_public_key_der(&bytes)
-                        .expect("rsa key was already validated in parse_auth_event"),
-                )
-            }
-        };
-        Ok(rebuilt)
     }
 }

server/crates/arbiter-server/src/actors/user_agent/mod.rs

@@ -1,65 +1,94 @@
-use arbiter_proto::{
-    proto::user_agent::{UserAgentRequest, UserAgentResponse},
-    transport::Bi,
-};
-use kameo::actor::Spawn as _;
-use tracing::{error, info};
-
 use crate::{
-    actors::{GlobalActors, user_agent::session::UserAgentSession},
+    actors::{GlobalActors, client::ClientProfile},
-    db::{self},
+    db::{self, models::KeyType},
 };
 
-#[derive(Debug, thiserror::Error, PartialEq)]
+/// Abstraction over Ed25519 / ECDSA-secp256k1 / RSA public keys used during the auth handshake.
-pub enum TransportResponseError {
+#[derive(Clone, Debug)]
-    #[error("Expected message with payload")]
+pub enum AuthPublicKey {
-    MissingRequestPayload,
+    Ed25519(ed25519_dalek::VerifyingKey),
-    #[error("Unexpected request payload")]
+    /// Compressed SEC1 public key; signature bytes are raw 64-byte (r||s).
-    UnexpectedRequestPayload,
+    EcdsaSecp256k1(k256::ecdsa::VerifyingKey),
-    #[error("Invalid state for unseal encrypted key")]
+    /// RSA-2048+ public key (Windows Hello / KeyCredentialManager); signature bytes are PSS+SHA-256.
-    InvalidStateForUnsealEncryptedKey,
+    Rsa(rsa::RsaPublicKey),
-    #[error("client_pubkey must be 32 bytes")]
-    InvalidClientPubkeyLength,
-    #[error("State machine error")]
-    StateTransitionFailed,
-    #[error("Vault is not available")]
-    KeyHolderActorUnreachable,
-    #[error(transparent)]
-    Auth(#[from] auth::Error),
-    #[error("Failed registering connection")]
-    ConnectionRegistrationFailed,
 }
 
-pub type Transport =
+impl AuthPublicKey {
-    Box<dyn Bi<UserAgentRequest, Result<UserAgentResponse, TransportResponseError>> + Send>;
+    /// Canonical bytes stored in DB and echoed back in the challenge.
+    /// Ed25519: raw 32 bytes. ECDSA: SEC1 compressed 33 bytes. RSA: DER-encoded SPKI.
+    pub fn to_stored_bytes(&self) -> Vec<u8> {
+        match self {
+            AuthPublicKey::Ed25519(k) => k.to_bytes().to_vec(),
+            // SEC1 compressed (33 bytes) is the natural compact format for secp256k1
+            AuthPublicKey::EcdsaSecp256k1(k) => k.to_encoded_point(true).as_bytes().to_vec(),
+            AuthPublicKey::Rsa(k) => {
+                use rsa::pkcs8::EncodePublicKey as _;
+                #[allow(clippy::expect_used)]
+                k.to_public_key_der()
+                    .expect("rsa SPKI encoding is infallible")
+                    .to_vec()
+            }
+        }
+    }
+
+    pub fn key_type(&self) -> KeyType {
+        match self {
+            AuthPublicKey::Ed25519(_) => KeyType::Ed25519,
+            AuthPublicKey::EcdsaSecp256k1(_) => KeyType::EcdsaSecp256k1,
+            AuthPublicKey::Rsa(_) => KeyType::Rsa,
+        }
+    }
+}
+
+impl TryFrom<(KeyType, Vec<u8>)> for AuthPublicKey {
+    type Error = &'static str;
+
+    fn try_from(value: (KeyType, Vec<u8>)) -> Result<Self, Self::Error> {
+        let (key_type, bytes) = value;
+        match key_type {
+            KeyType::Ed25519 => {
+                let bytes: [u8; 32] = bytes.try_into().map_err(|_| "invalid Ed25519 key length")?;
+                let key = ed25519_dalek::VerifyingKey::from_bytes(&bytes)
+                    .map_err(|_e| "invalid Ed25519 key")?;
+                Ok(AuthPublicKey::Ed25519(key))
+            }
+            KeyType::EcdsaSecp256k1 => {
+                let point =
+                    k256::EncodedPoint::from_bytes(&bytes).map_err(|_e| "invalid ECDSA key")?;
+                let key = k256::ecdsa::VerifyingKey::from_encoded_point(&point)
+                    .map_err(|_e| "invalid ECDSA key")?;
+                Ok(AuthPublicKey::EcdsaSecp256k1(key))
+            }
+            KeyType::Rsa => {
+                use rsa::pkcs8::DecodePublicKey as _;
+                let key = rsa::RsaPublicKey::from_public_key_der(&bytes)
+                    .map_err(|_e| "invalid RSA key")?;
+                Ok(AuthPublicKey::Rsa(key))
+            }
+        }
+    }
+}
+
+// Messages, sent by user agent to connection client without having a request
+#[derive(Debug)]
+pub enum OutOfBand {
+    ClientConnectionRequest { profile: ClientProfile },
+    ClientConnectionCancel { pubkey: ed25519_dalek::VerifyingKey },
+}
 
 pub struct UserAgentConnection {
-    db: db::DatabasePool,
+    pub(crate) db: db::DatabasePool,
-    actors: GlobalActors,
+    pub(crate) actors: GlobalActors,
-    transport: Transport,
 }
 
 impl UserAgentConnection {
-    pub fn new(db: db::DatabasePool, actors: GlobalActors, transport: Transport) -> Self {
+    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
-        Self {
+        Self { db, actors }
-            db,
-            actors,
-            transport,
-        }
     }
 }
 
 pub mod auth;
 pub mod session;
 
-pub async fn connect_user_agent(props: UserAgentConnection) {
+pub use auth::authenticate;
-    match auth::authenticate_and_create(props).await {
+pub use session::UserAgentSession;
-        Ok(session) => {
-            UserAgentSession::spawn(session);
-            info!("User authenticated, session started");
-        }
-        Err(err) => {
-            error!(?err, "Authentication failed, closing connection");
-        }
-    }
-}

server/crates/arbiter-server/src/actors/user_agent/session.rs

@@ -1,523 +1,132 @@
-use std::{ops::DerefMut, sync::Mutex};
+use std::{borrow::Cow, collections::HashMap};
 
-use arbiter_proto::proto::{
+use arbiter_proto::transport::Sender;
-    evm as evm_proto,
+use async_trait::async_trait;
-    user_agent::{
+use ed25519_dalek::VerifyingKey;
-        SdkClientApproveRequest, SdkClientApproveResponse, SdkClientEntry,
+use kameo::{Actor, actor::ActorRef, messages};
-        SdkClientError as ProtoSdkClientError, SdkClientList, SdkClientListResponse,
+use thiserror::Error;
-        SdkClientRevokeRequest, SdkClientRevokeResponse, UnsealEncryptedKey, UnsealResult,
+use tracing::error;
-        UnsealStart, UnsealStartResponse, UserAgentRequest, UserAgentResponse,
-        sdk_client_approve_response, sdk_client_list_response, sdk_client_revoke_response,
-        user_agent_request::Payload as UserAgentRequestPayload,
-        user_agent_response::Payload as UserAgentResponsePayload,
-    },
-};
-use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use diesel::{ExpressionMethods as _, QueryDsl as _, dsl::insert_into};
-use diesel_async::RunQueryDsl as _;
-use kameo::{Actor, error::SendError, prelude::Context};
-use memsafe::MemSafe;
-use tokio::select;
-use tracing::{error, info};
-use x25519_dalek::{EphemeralSecret, PublicKey};
 
-use crate::{
+use crate::actors::{
-    actors::{
+    client::ClientProfile,
-        evm::{Generate, ListWallets},
+    flow_coordinator::{RegisterUserAgent, client_connect_approval::ClientApprovalController},
-        keyholder::{self, TryUnseal},
+    user_agent::{OutOfBand, UserAgentConnection},
-        router::RegisterUserAgent,
-        user_agent::{TransportResponseError, UserAgentConnection},
-    },
-    db::schema::program_client,
 };
 
 mod state;
-use state::{DummyContext, UnsealContext, UserAgentEvents, UserAgentStateMachine, UserAgentStates};
+use state::{DummyContext, UserAgentEvents, UserAgentStateMachine};
 
-// Error for consumption by other actors
+#[derive(Debug, Error)]
-#[derive(Debug, thiserror::Error, PartialEq)]
 pub enum Error {
-    #[error("User agent session ended due to connection loss")]
+    #[error("State transition failed")]
-    ConnectionLost,
+    State,
 
-    #[error("User agent session ended due to unexpected message")]
+    #[error("Internal error: {message}")]
-    UnexpectedMessage,
+    Internal { message: Cow<'static, str> },
+}
+
+impl From<crate::db::PoolError> for Error {
+    fn from(err: crate::db::PoolError) -> Self {
+        error!(?err, "Database pool error");
+        Self::internal("Database pool error")
+    }
+}
+impl From<diesel::result::Error> for Error {
+    fn from(err: diesel::result::Error) -> Self {
+        error!(?err, "Database error");
+        Self::internal("Database error")
+    }
+}
+
+impl Error {
+    pub fn internal(message: impl Into<Cow<'static, str>>) -> Self {
+        Self::Internal {
+            message: message.into(),
+        }
+    }
+}
+
+pub struct PendingClientApproval {
+    controller: ActorRef<ClientApprovalController>,
 }
 
 pub struct UserAgentSession {
     props: UserAgentConnection,
     state: UserAgentStateMachine<DummyContext>,
+    sender: Box<dyn Sender<OutOfBand>>,
+
+    pending_client_approvals: HashMap<VerifyingKey, PendingClientApproval>,
 }
 
+pub mod connection;
+
 impl UserAgentSession {
-    pub(crate) fn new(props: UserAgentConnection) -> Self {
+    pub(crate) fn new(props: UserAgentConnection, sender: Box<dyn Sender<OutOfBand>>) -> Self {
         Self {
             props,
             state: UserAgentStateMachine::new(DummyContext),
+            sender,
+            pending_client_approvals: Default::default(),
         }
     }
 
-    fn transition(&mut self, event: UserAgentEvents) -> Result<(), TransportResponseError> {
+    pub fn new_test(db: crate::db::DatabasePool, actors: crate::actors::GlobalActors) -> Self {
+        struct DummySender;
+
+        #[async_trait]
+        impl Sender<OutOfBand> for DummySender {
+            async fn send(
+                &mut self,
+                _item: OutOfBand,
+            ) -> Result<(), arbiter_proto::transport::Error> {
+                Ok(())
+            }
+        }
+
+        Self::new(UserAgentConnection::new(db, actors), Box::new(DummySender))
+    }
+
+    fn transition(&mut self, event: UserAgentEvents) -> Result<(), Error> {
         self.state.process_event(event).map_err(|e| {
             error!(?e, "State transition failed");
-            TransportResponseError::StateTransitionFailed
+            Error::State
         })?;
         Ok(())
     }
+}
 
-    async fn send_msg<Reply: kameo::Reply>(
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub async fn begin_new_client_approval(
         &mut self,
-        msg: UserAgentResponsePayload,
+        client: ClientProfile,
-        _ctx: &mut Context<Self, Reply>,
+        controller: ActorRef<ClientApprovalController>,
-    ) -> Result<(), Error> {
+    ) {
-        self.props
+        if let Err(e) = self
-            .transport
+            .sender
-            .send(Ok(response(msg)))
+            .send(OutOfBand::ClientConnectionRequest {
+                profile: client.clone(),
+            })
             .await
-            .map_err(|_| {
+        {
             error!(
-                    actor = "useragent",
+                ?e,
-                    reason = "channel closed",
+                actor = "user_agent",
-                    "send.failed"
+                event = "failed to announce new client connection"
             );
-                Error::ConnectionLost
+            return;
-            })
         }
 
-    async fn expect_msg<Extractor, Msg, Reply>(
+        self.pending_client_approvals
-        &mut self,
+            .insert(client.pubkey, PendingClientApproval { controller });
-        extractor: Extractor,
-        ctx: &mut Context<Self, Reply>,
-    ) -> Result<Msg, Error>
-    where
-        Extractor: FnOnce(UserAgentRequestPayload) -> Option<Msg>,
-        Reply: kameo::Reply,
-    {
-        let msg = self.props.transport.recv().await.ok_or_else(|| {
-            error!(
-                actor = "useragent",
-                reason = "channel closed",
-                "recv.failed"
-            );
-            ctx.stop();
-            Error::ConnectionLost
-        })?;
-
-        msg.payload.and_then(extractor).ok_or_else(|| {
-            error!(
-                actor = "useragent",
-                reason = "unexpected message",
-                "recv.failed"
-            );
-            ctx.stop();
-            Error::UnexpectedMessage
-        })
-    }
-}
-
-impl UserAgentSession {
-    pub async fn process_transport_inbound(&mut self, req: UserAgentRequest) -> Output {
-        let msg = req.payload.ok_or_else(|| {
-            error!(actor = "useragent", "Received message with no payload");
-            TransportResponseError::MissingRequestPayload
-        })?;
-
-        match msg {
-            UserAgentRequestPayload::UnsealStart(unseal_start) => {
-                self.handle_unseal_request(unseal_start).await
-            }
-            UserAgentRequestPayload::UnsealEncryptedKey(unseal_encrypted_key) => {
-                self.handle_unseal_encrypted_key(unseal_encrypted_key).await
-            }
-            UserAgentRequestPayload::EvmWalletCreate(_) => self.handle_evm_wallet_create().await,
-            UserAgentRequestPayload::EvmWalletList(_) => self.handle_evm_wallet_list().await,
-            UserAgentRequestPayload::SdkClientApprove(req) => {
-                self.handle_sdk_client_approve(req).await
-            }
-            UserAgentRequestPayload::SdkClientRevoke(req) => {
-                self.handle_sdk_client_revoke(req).await
-            }
-            UserAgentRequestPayload::SdkClientList(_) => self.handle_sdk_client_list().await,
-            _ => Err(TransportResponseError::UnexpectedRequestPayload),
-        }
-    }
-}
-
-type Output = Result<UserAgentResponse, TransportResponseError>;
-
-fn response(payload: UserAgentResponsePayload) -> UserAgentResponse {
-    UserAgentResponse {
-        payload: Some(payload),
-    }
-}
-
-impl UserAgentSession {
-    async fn handle_unseal_request(&mut self, req: UnsealStart) -> Output {
-        let secret = EphemeralSecret::random();
-        let public_key = PublicKey::from(&secret);
-
-        let client_pubkey_bytes: [u8; 32] = req
-            .client_pubkey
-            .try_into()
-            .map_err(|_| TransportResponseError::InvalidClientPubkeyLength)?;
-
-        let client_public_key = PublicKey::from(client_pubkey_bytes);
-
-        self.transition(UserAgentEvents::UnsealRequest(UnsealContext {
-            secret: Mutex::new(Some(secret)),
-            client_public_key,
-        }))?;
-
-        Ok(response(UserAgentResponsePayload::UnsealStartResponse(
-            UnsealStartResponse {
-                server_pubkey: public_key.as_bytes().to_vec(),
-            },
-        )))
-    }
-
-    async fn handle_unseal_encrypted_key(&mut self, req: UnsealEncryptedKey) -> Output {
-        let UserAgentStates::WaitingForUnsealKey(unseal_context) = self.state.state() else {
-            error!("Received unseal encrypted key in invalid state");
-            return Err(TransportResponseError::InvalidStateForUnsealEncryptedKey);
-        };
-        let ephemeral_secret = {
-            let mut secret_lock = unseal_context.secret.lock().unwrap();
-            let secret = secret_lock.take();
-            match secret {
-                Some(secret) => secret,
-                None => {
-                    drop(secret_lock);
-                    error!("Ephemeral secret already taken");
-                    self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                    return Ok(response(UserAgentResponsePayload::UnsealResult(
-                        UnsealResult::InvalidKey.into(),
-                    )));
-                }
-            }
-        };
-
-        let nonce = XNonce::from_slice(&req.nonce);
-
-        let shared_secret = ephemeral_secret.diffie_hellman(&unseal_context.client_public_key);
-        let cipher = XChaCha20Poly1305::new(shared_secret.as_bytes().into());
-
-        let mut seal_key_buffer = MemSafe::new(req.ciphertext.clone()).unwrap();
-
-        let decryption_result = {
-            let mut write_handle = seal_key_buffer.write().unwrap();
-            let write_handle = write_handle.deref_mut();
-            cipher.decrypt_in_place(nonce, &req.associated_data, write_handle)
-        };
-
-        match decryption_result {
-            Ok(_) => {
-                match self
-                    .props
-                    .actors
-                    .key_holder
-                    .ask(TryUnseal {
-                        seal_key_raw: seal_key_buffer,
-                    })
-                    .await
-                {
-                    Ok(_) => {
-                        info!("Successfully unsealed key with client-provided key");
-                        self.transition(UserAgentEvents::ReceivedValidKey)?;
-                        Ok(response(UserAgentResponsePayload::UnsealResult(
-                            UnsealResult::Success.into(),
-                        )))
-                    }
-                    Err(SendError::HandlerError(keyholder::Error::InvalidKey)) => {
-                        self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                        Ok(response(UserAgentResponsePayload::UnsealResult(
-                            UnsealResult::InvalidKey.into(),
-                        )))
-                    }
-                    Err(SendError::HandlerError(err)) => {
-                        error!(?err, "Keyholder failed to unseal key");
-                        self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                        Ok(response(UserAgentResponsePayload::UnsealResult(
-                            UnsealResult::InvalidKey.into(),
-                        )))
-                    }
-                    Err(err) => {
-                        error!(?err, "Failed to send unseal request to keyholder");
-                        self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                        Err(TransportResponseError::KeyHolderActorUnreachable)
-                    }
-                }
-            }
-            Err(err) => {
-                error!(?err, "Failed to decrypt unseal key");
-                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
-                Ok(response(UserAgentResponsePayload::UnsealResult(
-                    UnsealResult::InvalidKey.into(),
-                )))
-            }
-        }
-    }
-}
-
-impl UserAgentSession {
-    async fn handle_evm_wallet_create(&mut self) -> Output {
-        use evm_proto::wallet_create_response::Result as CreateResult;
-
-        let result = match self.props.actors.evm.ask(Generate {}).await {
-            Ok(address) => CreateResult::Wallet(evm_proto::WalletEntry {
-                address: address.as_slice().to_vec(),
-            }),
-            Err(err) => CreateResult::Error(map_evm_error("wallet create", err).into()),
-        };
-
-        Ok(response(UserAgentResponsePayload::EvmWalletCreate(
-            evm_proto::WalletCreateResponse {
-                result: Some(result),
-            },
-        )))
-    }
-
-    async fn handle_evm_wallet_list(&mut self) -> Output {
-        use evm_proto::wallet_list_response::Result as ListResult;
-
-        let result = match self.props.actors.evm.ask(ListWallets {}).await {
-            Ok(wallets) => ListResult::Wallets(evm_proto::WalletList {
-                wallets: wallets
-                    .into_iter()
-                    .map(|addr| evm_proto::WalletEntry {
-                        address: addr.as_slice().to_vec(),
-                    })
-                    .collect(),
-            }),
-            Err(err) => ListResult::Error(map_evm_error("wallet list", err).into()),
-        };
-
-        Ok(response(UserAgentResponsePayload::EvmWalletList(
-            evm_proto::WalletListResponse {
-                result: Some(result),
-            },
-        )))
-    }
-}
-
-impl UserAgentSession {
-    async fn handle_sdk_client_approve(&mut self, req: SdkClientApproveRequest) -> Output {
-        use sdk_client_approve_response::Result as ApproveResult;
-
-        if req.pubkey.len() != 32 {
-            return Ok(response(UserAgentResponsePayload::SdkClientApprove(
-                SdkClientApproveResponse {
-                    result: Some(ApproveResult::Error(ProtoSdkClientError::Internal.into())),
-                },
-            )));
-        }
-
-        let now = std::time::SystemTime::now()
-            .duration_since(std::time::UNIX_EPOCH)
-            .unwrap_or_default()
-            .as_secs() as i32;
-
-        let mut conn = match self.props.db.get().await {
-            Ok(c) => c,
-            Err(e) => {
-                error!(?e, "Failed to get DB connection for sdk_client_approve");
-                return Ok(response(UserAgentResponsePayload::SdkClientApprove(
-                    SdkClientApproveResponse {
-                        result: Some(ApproveResult::Error(ProtoSdkClientError::Internal.into())),
-                    },
-                )));
-            }
-        };
-
-        let pubkey_bytes = req.pubkey.clone();
-        let insert_result = insert_into(program_client::table)
-            .values((
-                program_client::public_key.eq(&pubkey_bytes),
-                program_client::nonce.eq(1), // pre-incremented; challenge will use nonce=0
-                program_client::created_at.eq(now),
-                program_client::updated_at.eq(now),
-            ))
-            .execute(&mut conn)
-            .await;
-
-        match insert_result {
-            Ok(_) => {
-                match program_client::table
-                    .filter(program_client::public_key.eq(&pubkey_bytes))
-                    .order(program_client::id.desc())
-                    .select((
-                        program_client::id,
-                        program_client::public_key,
-                        program_client::created_at,
-                    ))
-                    .first::<(i32, Vec<u8>, i32)>(&mut conn)
-                    .await
-                {
-                    Ok((id, pubkey, created_at)) => Ok(response(
-                        UserAgentResponsePayload::SdkClientApprove(SdkClientApproveResponse {
-                            result: Some(ApproveResult::Client(SdkClientEntry {
-                                id,
-                                pubkey,
-                                created_at,
-                            })),
-                        }),
-                    )),
-                    Err(e) => {
-                        error!(?e, "Failed to fetch inserted SDK client");
-                        Ok(response(UserAgentResponsePayload::SdkClientApprove(
-                            SdkClientApproveResponse {
-                                result: Some(ApproveResult::Error(
-                                    ProtoSdkClientError::Internal.into(),
-                                )),
-                            },
-                        )))
-                    }
-                }
-            }
-            Err(diesel::result::Error::DatabaseError(
-                diesel::result::DatabaseErrorKind::UniqueViolation,
-                _,
-            )) => Ok(response(UserAgentResponsePayload::SdkClientApprove(
-                SdkClientApproveResponse {
-                    result: Some(ApproveResult::Error(
-                        ProtoSdkClientError::AlreadyExists.into(),
-                    )),
-                },
-            ))),
-            Err(e) => {
-                error!(?e, "Failed to insert SDK client");
-                Ok(response(UserAgentResponsePayload::SdkClientApprove(
-                    SdkClientApproveResponse {
-                        result: Some(ApproveResult::Error(ProtoSdkClientError::Internal.into())),
-                    },
-                )))
-            }
-        }
-    }
-
-    async fn handle_sdk_client_list(&mut self) -> Output {
-        let mut conn = match self.props.db.get().await {
-            Ok(c) => c,
-            Err(e) => {
-                error!(?e, "Failed to get DB connection for sdk_client_list");
-                return Ok(response(UserAgentResponsePayload::SdkClientList(
-                    SdkClientListResponse {
-                        result: Some(sdk_client_list_response::Result::Error(
-                            ProtoSdkClientError::Internal.into(),
-                        )),
-                    },
-                )));
-            }
-        };
-
-        match program_client::table
-            .select((
-                program_client::id,
-                program_client::public_key,
-                program_client::created_at,
-            ))
-            .load::<(i32, Vec<u8>, i32)>(&mut conn)
-            .await
-        {
-            Ok(rows) => Ok(response(UserAgentResponsePayload::SdkClientList(
-                SdkClientListResponse {
-                    result: Some(sdk_client_list_response::Result::Clients(SdkClientList {
-                        clients: rows
-                            .into_iter()
-                            .map(|(id, pubkey, created_at)| SdkClientEntry {
-                                id,
-                                pubkey,
-                                created_at,
-                            })
-                            .collect(),
-                    })),
-                },
-            ))),
-            Err(e) => {
-                error!(?e, "Failed to list SDK clients");
-                Ok(response(UserAgentResponsePayload::SdkClientList(
-                    SdkClientListResponse {
-                        result: Some(sdk_client_list_response::Result::Error(
-                            ProtoSdkClientError::Internal.into(),
-                        )),
-                    },
-                )))
-            }
-        }
-    }
-
-    async fn handle_sdk_client_revoke(&mut self, req: SdkClientRevokeRequest) -> Output {
-        use sdk_client_revoke_response::Result as RevokeResult;
-
-        let mut conn = match self.props.db.get().await {
-            Ok(c) => c,
-            Err(e) => {
-                error!(?e, "Failed to get DB connection for sdk_client_revoke");
-                return Ok(response(UserAgentResponsePayload::SdkClientRevoke(
-                    SdkClientRevokeResponse {
-                        result: Some(RevokeResult::Error(ProtoSdkClientError::Internal.into())),
-                    },
-                )));
-            }
-        };
-
-        match diesel::delete(program_client::table)
-            .filter(program_client::id.eq(req.client_id))
-            .execute(&mut conn)
-            .await
-        {
-            Ok(0) => Ok(response(UserAgentResponsePayload::SdkClientRevoke(
-                SdkClientRevokeResponse {
-                    result: Some(RevokeResult::Error(ProtoSdkClientError::NotFound.into())),
-                },
-            ))),
-            Ok(_) => Ok(response(UserAgentResponsePayload::SdkClientRevoke(
-                SdkClientRevokeResponse {
-                    result: Some(RevokeResult::Ok(())),
-                },
-            ))),
-            Err(diesel::result::Error::DatabaseError(
-                diesel::result::DatabaseErrorKind::ForeignKeyViolation,
-                _,
-            )) => Ok(response(UserAgentResponsePayload::SdkClientRevoke(
-                SdkClientRevokeResponse {
-                    result: Some(RevokeResult::Error(
-                        ProtoSdkClientError::HasRelatedData.into(),
-                    )),
-                },
-            ))),
-            Err(e) => {
-                error!(?e, "Failed to delete SDK client");
-                Ok(response(UserAgentResponsePayload::SdkClientRevoke(
-                    SdkClientRevokeResponse {
-                        result: Some(RevokeResult::Error(ProtoSdkClientError::Internal.into())),
-                    },
-                )))
-            }
-        }
-    }
-}
-
-fn map_evm_error<M>(op: &str, err: SendError<M, crate::actors::evm::Error>) -> evm_proto::EvmError {
-    use crate::actors::{evm::Error as EvmError, keyholder::Error as KhError};
-    match err {
-        SendError::HandlerError(EvmError::Keyholder(KhError::NotBootstrapped)) => {
-            evm_proto::EvmError::VaultSealed
-        }
-        SendError::HandlerError(err) => {
-            error!(?err, "EVM {op} failed");
-            evm_proto::EvmError::Internal
-        }
-        _ => {
-            error!("EVM actor unreachable during {op}");
-            evm_proto::EvmError::Internal
-        }
     }
 }
 
 impl Actor for UserAgentSession {
     type Args = Self;
 
-    type Error = TransportResponseError;
+    type Error = Error;
 
     async fn on_start(
         args: Self::Args,
@@ -525,63 +134,48 @@ impl Actor for UserAgentSession {
     ) -> Result<Self, Self::Error> {
         args.props
             .actors
-            .router
+            .flow_coordinator
             .ask(RegisterUserAgent {
                 actor: this.clone(),
             })
             .await
             .map_err(|err| {
-                error!(?err, "Failed to register user agent connection with router");
+                error!(
-                TransportResponseError::ConnectionRegistrationFailed
+                    ?err,
+                    "Failed to register user agent connection with flow coordinator"
+                );
+                Error::internal("Failed to register user agent connection with flow coordinator")
             })?;
         Ok(args)
     }
 
-    async fn next(
+    async fn on_link_died(
         &mut self,
-        _actor_ref: kameo::prelude::WeakActorRef<Self>,
+        _: kameo::prelude::WeakActorRef<Self>,
-        mailbox_rx: &mut kameo::prelude::MailboxReceiver<Self>,
+        id: kameo::prelude::ActorId,
-    ) -> Option<kameo::mailbox::Signal<Self>> {
+        _: kameo::prelude::ActorStopReason,
-        loop {
+    ) -> Result<std::ops::ControlFlow<kameo::prelude::ActorStopReason>, Self::Error> {
-            select! {
+        let cancelled_pubkey = self
-                signal = mailbox_rx.recv() => {
+            .pending_client_approvals
-                    return signal;
+            .iter()
-                }
+            .find_map(|(k, v)| (v.controller.id() == id).then_some(*k));
-                msg = self.props.transport.recv() => {
-                    match msg {
-                        Some(request) => {
-                            match self.process_transport_inbound(request).await {
-                                Ok(response) => {
-                                    if self.props.transport.send(Ok(response)).await.is_err() {
-                                        error!(actor = "useragent", reason = "channel closed", "send.failed");
-                                        return Some(kameo::mailbox::Signal::Stop);
-                                    }
-                                }
-                                Err(err) => {
-                                    let _ = self.props.transport.send(Err(err)).await;
-                                    return Some(kameo::mailbox::Signal::Stop);
-                                }
-                            }
-                        }
-                        None => {
-                            info!(actor = "useragent", "transport.closed");
-                            return Some(kameo::mailbox::Signal::Stop);
-                        }
-                    }
-                }
-            }
-        }
-    }
-}
 
-impl UserAgentSession {
+        if let Some(pubkey) = cancelled_pubkey {
-    pub fn new_test(db: crate::db::DatabasePool, actors: crate::actors::GlobalActors) -> Self {
+            self.pending_client_approvals.remove(&pubkey);
-        use arbiter_proto::transport::DummyTransport;
+
-        let transport: super::Transport = Box::new(DummyTransport::new());
+            if let Err(e) = self
-        let props = UserAgentConnection::new(db, actors, transport);
+                .sender
-        Self {
+                .send(OutOfBand::ClientConnectionCancel { pubkey })
-            props,
+                .await
-            state: UserAgentStateMachine::new(DummyContext),
+            {
+                error!(
+                    ?e,
+                    actor = "user_agent",
+                    event = "failed to announce client connection cancellation"
+                );
             }
         }
+
+        Ok(std::ops::ControlFlow::Continue(()))
+    }
 }

server/crates/arbiter-server/src/actors/user_agent/session/connection.rs

@@ -0,0 +1,510 @@
+use std::sync::Mutex;
+
+use alloy::{consensus::TxEip1559, primitives::Address, signers::Signature};
+use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
+use diesel::{ExpressionMethods as _, QueryDsl as _, SelectableHelper};
+use diesel_async::{AsyncConnection, RunQueryDsl};
+use kameo::error::SendError;
+use kameo::messages;
+use kameo::prelude::Context;
+use tracing::{error, info};
+use x25519_dalek::{EphemeralSecret, PublicKey};
+
+use crate::actors::flow_coordinator::client_connect_approval::ClientApprovalAnswer;
+use crate::actors::keyholder::KeyHolderState;
+use crate::actors::user_agent::session::Error;
+use crate::db::models::{
+    EvmWalletAccess, NewEvmWalletAccess, ProgramClient, ProgramClientMetadata,
+};
+use crate::evm::policies::{Grant, SpecificGrant};
+use crate::safe_cell::SafeCell;
+use crate::{
+    actors::{
+        evm::{
+            ClientSignTransaction, Generate, ListWallets, SignTransactionError as EvmSignError,
+            UseragentCreateGrant, UseragentDeleteGrant, UseragentListGrants,
+        },
+        keyholder::{self, Bootstrap, TryUnseal},
+        user_agent::session::{
+            UserAgentSession,
+            state::{UnsealContext, UserAgentEvents, UserAgentStates},
+        },
+    },
+    safe_cell::SafeCellHandle as _,
+};
+
+impl UserAgentSession {
+    fn take_unseal_secret(&mut self) -> Result<(EphemeralSecret, PublicKey), Error> {
+        let UserAgentStates::WaitingForUnsealKey(unseal_context) = self.state.state() else {
+            error!("Received encrypted key in invalid state");
+            return Err(Error::internal("Invalid state for unseal encrypted key"));
+        };
+
+        let ephemeral_secret = {
+            #[allow(
+                clippy::unwrap_used,
+                reason = "Mutex poison is unrecoverable and should panic"
+            )]
+            let mut secret_lock = unseal_context.secret.lock().unwrap();
+            let secret = secret_lock.take();
+            match secret {
+                Some(secret) => secret,
+                None => {
+                    drop(secret_lock);
+                    error!("Ephemeral secret already taken");
+                    return Err(Error::internal("Ephemeral secret already taken"));
+                }
+            }
+        };
+
+        Ok((ephemeral_secret, unseal_context.client_public_key))
+    }
+
+    fn decrypt_client_key_material(
+        ephemeral_secret: EphemeralSecret,
+        client_public_key: PublicKey,
+        nonce: &[u8],
+        ciphertext: &[u8],
+        associated_data: &[u8],
+    ) -> Result<SafeCell<Vec<u8>>, ()> {
+        let nonce = XNonce::from_slice(nonce);
+
+        let shared_secret = ephemeral_secret.diffie_hellman(&client_public_key);
+        let cipher = XChaCha20Poly1305::new(shared_secret.as_bytes().into());
+
+        let mut key_buffer = SafeCell::new(ciphertext.to_vec());
+
+        let decryption_result = key_buffer.write_inline(|write_handle| {
+            cipher.decrypt_in_place(nonce, associated_data, write_handle)
+        });
+
+        match decryption_result {
+            Ok(_) => Ok(key_buffer),
+            Err(err) => {
+                error!(?err, "Failed to decrypt encrypted key material");
+                Err(())
+            }
+        }
+    }
+}
+
+pub struct UnsealStartResponse {
+    pub server_pubkey: PublicKey,
+}
+
+#[derive(Debug, Error)]
+pub enum UnsealError {
+    #[error("Invalid key provided for unsealing")]
+    InvalidKey,
+    #[error("Internal error during unsealing process")]
+    General(#[from] super::Error),
+}
+
+#[derive(Debug, Error)]
+pub enum BootstrapError {
+    #[error("Invalid key provided for bootstrapping")]
+    InvalidKey,
+    #[error("Vault is already bootstrapped")]
+    AlreadyBootstrapped,
+
+    #[error("Internal error during bootstrapping process")]
+    General(#[from] super::Error),
+}
+
+#[derive(Debug, Error)]
+pub enum SignTransactionError {
+    #[error("Policy evaluation failed")]
+    Vet(#[from] crate::evm::VetError),
+
+    #[error("Internal signing error")]
+    Internal,
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub async fn handle_unseal_request(
+        &mut self,
+        client_pubkey: x25519_dalek::PublicKey,
+    ) -> Result<UnsealStartResponse, Error> {
+        let secret = EphemeralSecret::random();
+        let public_key = PublicKey::from(&secret);
+
+        self.transition(UserAgentEvents::UnsealRequest(UnsealContext {
+            secret: Mutex::new(Some(secret)),
+            client_public_key: client_pubkey,
+        }))?;
+
+        Ok(UnsealStartResponse {
+            server_pubkey: public_key,
+        })
+    }
+
+    #[message]
+    pub async fn handle_unseal_encrypted_key(
+        &mut self,
+        nonce: Vec<u8>,
+        ciphertext: Vec<u8>,
+        associated_data: Vec<u8>,
+    ) -> Result<(), UnsealError> {
+        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
+            Ok(values) => values,
+            Err(Error::State) => {
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                return Err(UnsealError::InvalidKey);
+            }
+            Err(_err) => {
+                return Err(Error::internal("Failed to take unseal secret").into());
+            }
+        };
+
+        let seal_key_buffer = match Self::decrypt_client_key_material(
+            ephemeral_secret,
+            client_public_key,
+            &nonce,
+            &ciphertext,
+            &associated_data,
+        ) {
+            Ok(buffer) => buffer,
+            Err(()) => {
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                return Err(UnsealError::InvalidKey);
+            }
+        };
+
+        match self
+            .props
+            .actors
+            .key_holder
+            .ask(TryUnseal {
+                seal_key_raw: seal_key_buffer,
+            })
+            .await
+        {
+            Ok(_) => {
+                info!("Successfully unsealed key with client-provided key");
+                self.transition(UserAgentEvents::ReceivedValidKey)?;
+                Ok(())
+            }
+            Err(SendError::HandlerError(keyholder::Error::InvalidKey)) => {
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Err(UnsealError::InvalidKey)
+            }
+            Err(SendError::HandlerError(err)) => {
+                error!(?err, "Keyholder failed to unseal key");
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Err(UnsealError::InvalidKey)
+            }
+            Err(err) => {
+                error!(?err, "Failed to send unseal request to keyholder");
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Err(Error::internal("Vault actor error").into())
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_bootstrap_encrypted_key(
+        &mut self,
+        nonce: Vec<u8>,
+        ciphertext: Vec<u8>,
+        associated_data: Vec<u8>,
+    ) -> Result<(), BootstrapError> {
+        let (ephemeral_secret, client_public_key) = match self.take_unseal_secret() {
+            Ok(values) => values,
+            Err(Error::State) => {
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                return Err(BootstrapError::InvalidKey);
+            }
+            Err(err) => return Err(err.into()),
+        };
+
+        let seal_key_buffer = match Self::decrypt_client_key_material(
+            ephemeral_secret,
+            client_public_key,
+            &nonce,
+            &ciphertext,
+            &associated_data,
+        ) {
+            Ok(buffer) => buffer,
+            Err(()) => {
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                return Err(BootstrapError::InvalidKey);
+            }
+        };
+
+        match self
+            .props
+            .actors
+            .key_holder
+            .ask(Bootstrap {
+                seal_key_raw: seal_key_buffer,
+            })
+            .await
+        {
+            Ok(_) => {
+                info!("Successfully bootstrapped vault with client-provided key");
+                self.transition(UserAgentEvents::ReceivedValidKey)?;
+                Ok(())
+            }
+            Err(SendError::HandlerError(keyholder::Error::AlreadyBootstrapped)) => {
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Err(BootstrapError::AlreadyBootstrapped)
+            }
+            Err(SendError::HandlerError(err)) => {
+                error!(?err, "Keyholder failed to bootstrap vault");
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Err(BootstrapError::InvalidKey)
+            }
+            Err(err) => {
+                error!(?err, "Failed to send bootstrap request to keyholder");
+                self.transition(UserAgentEvents::ReceivedInvalidKey)?;
+                Err(BootstrapError::General(Error::internal(
+                    "Vault actor error",
+                )))
+            }
+        }
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_query_vault_state(&mut self) -> Result<KeyHolderState, Error> {
+        use crate::actors::keyholder::GetState;
+
+        let vault_state = match self.props.actors.key_holder.ask(GetState {}).await {
+            Ok(state) => state,
+            Err(err) => {
+                error!(?err, actor = "useragent", "keyholder.query.failed");
+                return Err(Error::internal("Vault is in broken state"));
+            }
+        };
+
+        Ok(vault_state)
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_evm_wallet_create(&mut self) -> Result<(i32, Address), Error> {
+        match self.props.actors.evm.ask(Generate {}).await {
+            Ok(address) => Ok(address),
+            Err(SendError::HandlerError(err)) => Err(Error::internal(format!(
+                "EVM wallet generation failed: {err}"
+            ))),
+            Err(err) => {
+                error!(?err, "EVM actor unreachable during wallet create");
+                Err(Error::internal("EVM actor unreachable"))
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_evm_wallet_list(&mut self) -> Result<Vec<(i32, Address)>, Error> {
+        match self.props.actors.evm.ask(ListWallets {}).await {
+            Ok(wallets) => Ok(wallets),
+            Err(err) => {
+                error!(?err, "EVM wallet list failed");
+                Err(Error::internal("Failed to list EVM wallets"))
+            }
+        }
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message]
+    pub(crate) async fn handle_grant_list(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
+        match self.props.actors.evm.ask(UseragentListGrants {}).await {
+            Ok(grants) => Ok(grants),
+            Err(err) => {
+                error!(?err, "EVM grant list failed");
+                Err(Error::internal("Failed to list EVM grants"))
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_grant_create(
+        &mut self,
+        basic: crate::evm::policies::SharedGrantSettings,
+        grant: crate::evm::policies::SpecificGrant,
+    ) -> Result<i32, Error> {
+        match self
+            .props
+            .actors
+            .evm
+            .ask(UseragentCreateGrant { basic, grant })
+            .await
+        {
+            Ok(grant_id) => Ok(grant_id),
+            Err(err) => {
+                error!(?err, "EVM grant create failed");
+                Err(Error::internal("Failed to create EVM grant"))
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_grant_delete(&mut self, grant_id: i32) -> Result<(), Error> {
+        match self
+            .props
+            .actors
+            .evm
+            .ask(UseragentDeleteGrant { grant_id })
+            .await
+        {
+            Ok(()) => Ok(()),
+            Err(err) => {
+                error!(?err, "EVM grant delete failed");
+                Err(Error::internal("Failed to delete EVM grant"))
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_sign_transaction(
+        &mut self,
+        client_id: i32,
+        wallet_address: Address,
+        transaction: TxEip1559,
+    ) -> Result<Signature, SignTransactionError> {
+        match self
+            .props
+            .actors
+            .evm
+            .ask(ClientSignTransaction {
+                client_id,
+                wallet_address,
+                transaction,
+            })
+            .await
+        {
+            Ok(signature) => Ok(signature),
+            Err(SendError::HandlerError(EvmSignError::Vet(vet_error))) => {
+                Err(SignTransactionError::Vet(vet_error))
+            }
+            Err(err) => {
+                error!(?err, "EVM sign transaction failed in user-agent session");
+                Err(SignTransactionError::Internal)
+            }
+        }
+    }
+
+    #[message]
+    pub(crate) async fn handle_grant_evm_wallet_access(
+        &mut self,
+        entries: Vec<NewEvmWalletAccess>,
+    ) -> Result<(), Error> {
+        let mut conn = self.props.db.get().await?;
+        conn.transaction(|conn| {
+            Box::pin(async move {
+                use crate::db::schema::evm_wallet_access;
+
+                for entry in entries {
+                    diesel::insert_into(evm_wallet_access::table)
+                        .values(&entry)
+                        .on_conflict_do_nothing()
+                        .execute(conn)
+                        .await?;
+                }
+
+                Result::<_, Error>::Ok(())
+            })
+        })
+        .await?;
+        Ok(())
+    }
+
+    #[message]
+    pub(crate) async fn handle_revoke_evm_wallet_access(
+        &mut self,
+        entries: Vec<i32>,
+    ) -> Result<(), Error> {
+        let mut conn = self.props.db.get().await?;
+        conn.transaction(|conn| {
+            Box::pin(async move {
+                use crate::db::schema::evm_wallet_access;
+                for entry in entries {
+                    diesel::delete(evm_wallet_access::table)
+                        .filter(evm_wallet_access::wallet_id.eq(entry))
+                        .execute(conn)
+                        .await?;
+                }
+
+                Result::<_, Error>::Ok(())
+            })
+        })
+        .await?;
+        Ok(())
+    }
+
+    #[message]
+    pub(crate) async fn handle_list_wallet_access(
+        &mut self,
+    ) -> Result<Vec<EvmWalletAccess>, Error> {
+        let mut conn = self.props.db.get().await?;
+        use crate::db::schema::evm_wallet_access;
+        let access_entries = evm_wallet_access::table
+            .select(EvmWalletAccess::as_select())
+            .load::<_>(&mut conn)
+            .await?;
+        Ok(access_entries)
+    }
+}
+
+#[messages]
+impl UserAgentSession {
+    #[message(ctx)]
+    pub(crate) async fn handle_new_client_approve(
+        &mut self,
+        approved: bool,
+        pubkey: ed25519_dalek::VerifyingKey,
+        ctx: &mut Context<Self, Result<(), Error>>,
+    ) -> Result<(), Error> {
+        let pending_approval = match self.pending_client_approvals.remove(&pubkey) {
+            Some(approval) => approval,
+            None => {
+                error!("Received client connection response for unknown client");
+                return Err(Error::internal("Unknown client in connection response"));
+            }
+        };
+
+        pending_approval
+            .controller
+            .tell(ClientApprovalAnswer { approved })
+            .await
+            .map_err(|err| {
+                error!(
+                    ?err,
+                    "Failed to send client approval response to controller"
+                );
+                Error::internal("Failed to send client approval response to controller")
+            })?;
+
+        ctx.actor_ref().unlink(&pending_approval.controller).await;
+
+        Ok(())
+    }
+
+    #[message]
+    pub(crate) async fn handle_sdk_client_list(
+        &mut self,
+    ) -> Result<Vec<(ProgramClient, ProgramClientMetadata)>, Error> {
+        use crate::db::schema::{client_metadata, program_client};
+        let mut conn = self.props.db.get().await?;
+
+        let clients = program_client::table
+            .inner_join(client_metadata::table)
+            .select((
+                ProgramClient::as_select(),
+                ProgramClientMetadata::as_select(),
+            ))
+            .load::<(ProgramClient, ProgramClientMetadata)>(&mut conn)
+            .await?;
+
+        Ok(clients)
+    }
+}

server/crates/arbiter-server/src/context/mod.rs

@@ -1,6 +1,5 @@
 use std::sync::Arc;
 
-use miette::Diagnostic;
 use thiserror::Error;
 
 use crate::{
@@ -11,30 +10,24 @@ use crate::{
 
 pub mod tls;
 
-#[derive(Error, Debug, Diagnostic)]
+#[derive(Error, Debug)]
 pub enum InitError {
     #[error("Database setup failed: {0}")]
-    #[diagnostic(code(arbiter_server::init::database_setup))]
     DatabaseSetup(#[from] db::DatabaseSetupError),
 
     #[error("Connection acquire failed: {0}")]
-    #[diagnostic(code(arbiter_server::init::database_pool))]
     DatabasePool(#[from] db::PoolError),
 
     #[error("Database query error: {0}")]
-    #[diagnostic(code(arbiter_server::init::database_query))]
     DatabaseQuery(#[from] diesel::result::Error),
 
     #[error("TLS initialization failed: {0}")]
-    #[diagnostic(code(arbiter_server::init::tls_init))]
     Tls(#[from] tls::InitError),
 
     #[error("Actor spawn failed: {0}")]
-    #[diagnostic(code(arbiter_server::init::actor_spawn))]
     ActorSpawn(#[from] crate::actors::SpawnError),
 
     #[error("I/O Error: {0}")]
-    #[diagnostic(code(arbiter_server::init::io))]
     Io(#[from] std::io::Error),
 }
 

server/crates/arbiter-server/src/context/tls.rs

@@ -1,14 +1,14 @@
-use std::string::FromUtf8Error;
+use std::{net::Ipv4Addr, string::FromUtf8Error};
 
 use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper as _};
 use diesel_async::{AsyncConnection, RunQueryDsl};
-use miette::Diagnostic;
+
 use pem::Pem;
 use rcgen::{
     BasicConstraints, Certificate, CertificateParams, CertifiedIssuer, DistinguishedName, DnType,
-    IsCa, Issuer, KeyPair, KeyUsagePurpose,
+    IsCa, Issuer, KeyPair, KeyUsagePurpose, SanType,
 };
-use rustls::pki_types::{pem::PemObject};
+use rustls::pki_types::pem::PemObject;
 use thiserror::Error;
 use tonic::transport::CertificateDer;
 
@@ -29,40 +29,31 @@ const ENCODE_CONFIG: pem::EncodeConfig = {
     pem::EncodeConfig::new().set_line_ending(line_ending)
 };
 
-#[derive(Error, Debug, Diagnostic)]
+#[derive(Error, Debug)]
 pub enum InitError {
     #[error("Key generation error during TLS initialization: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::key_generation))]
     KeyGeneration(#[from] rcgen::Error),
 
     #[error("Key invalid format: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::key_invalid_format))]
     KeyInvalidFormat(#[from] FromUtf8Error),
 
     #[error("Key deserialization error: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::key_deserialization))]
     KeyDeserializationError(rcgen::Error),
 
     #[error("Database error during TLS initialization: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::database_error))]
     DatabaseError(#[from] diesel::result::Error),
 
     #[error("Pem deserialization error during TLS initialization: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::pem_deserialization))]
     PemDeserializationError(#[from] rustls::pki_types::pem::Error),
 
     #[error("Database pool acquire error during TLS initialization: {0}")]
-    #[diagnostic(code(arbiter_server::tls_init::database_pool_acquire))]
     DatabasePoolAcquire(#[from] db::PoolError),
 }
 
 pub type PemCert = String;
 
 pub fn encode_cert_to_pem(cert: &CertificateDer) -> PemCert {
-    pem::encode_config(
+    pem::encode_config(&Pem::new("CERTIFICATE", cert.to_vec()), ENCODE_CONFIG)
-        &Pem::new("CERTIFICATE", cert.to_vec()),
-        ENCODE_CONFIG,
-    )
 }
 
 #[allow(unused)]
@@ -94,6 +85,10 @@ impl TlsCa {
 
         let cert_key_pem = certified_issuer.key().serialize_pem();
 
+        #[allow(
+            clippy::unwrap_used,
+            reason = "Broken cert couldn't bootstrap server anyway"
+        )]
         let issuer = Issuer::from_ca_cert_pem(
             &certified_issuer.pem(),
             KeyPair::from_pem(cert_key_pem.as_ref()).unwrap(),
@@ -113,6 +108,9 @@ impl TlsCa {
             KeyUsagePurpose::DigitalSignature,
             KeyUsagePurpose::KeyEncipherment,
         ];
+        params
+            .subject_alt_names
+            .push(SanType::IpAddress(Ipv4Addr::LOCALHOST.into()));
 
         let mut dn = DistinguishedName::new();
         dn.push(DnType::CommonName, "Arbiter Instance Leaf");

server/crates/arbiter-server/src/crypto/encryption/v1.rs

@@ -0,0 +1,109 @@
+use argon2::password_hash::Salt as ArgonSalt;
+
+use rand::{
+    Rng as _, SeedableRng,
+    rngs::{StdRng, SysRng},
+};
+
+pub const ROOT_KEY_TAG: &[u8] = "arbiter/seal/v1".as_bytes();
+pub const TAG: &[u8] = "arbiter/private-key/v1".as_bytes();
+
+pub const NONCE_LENGTH: usize = 24;
+
+#[derive(Default)]
+pub struct Nonce(pub [u8; NONCE_LENGTH]);
+impl Nonce {
+    pub fn increment(&mut self) {
+        for i in (0..self.0.len()).rev() {
+            if self.0[i] == 0xFF {
+                self.0[i] = 0;
+            } else {
+                self.0[i] += 1;
+                break;
+            }
+        }
+    }
+
+    pub fn to_vec(&self) -> Vec<u8> {
+        self.0.to_vec()
+    }
+}
+impl<'a> TryFrom<&'a [u8]> for Nonce {
+    type Error = ();
+
+    fn try_from(value: &'a [u8]) -> Result<Self, Self::Error> {
+        if value.len() != NONCE_LENGTH {
+            return Err(());
+        }
+        let mut nonce = [0u8; NONCE_LENGTH];
+        nonce.copy_from_slice(value);
+        Ok(Self(nonce))
+    }
+}
+
+pub type Salt = [u8; ArgonSalt::RECOMMENDED_LENGTH];
+
+pub fn generate_salt() -> Salt {
+    let mut salt = Salt::default();
+    #[allow(
+        clippy::unwrap_used,
+        reason = "Rng failure is unrecoverable and should panic"
+    )]
+    let mut rng = StdRng::try_from_rng(&mut SysRng).unwrap();
+    rng.fill_bytes(&mut salt);
+    salt
+}
+
+#[cfg(test)]
+mod tests {
+    use std::ops::Deref as _;
+
+    use super::*;
+    use crate::{
+        crypto::derive_key,
+        safe_cell::{SafeCell, SafeCellHandle as _},
+    };
+
+    #[test]
+    pub fn derive_seal_key_deterministic() {
+        static PASSWORD: &[u8] = b"password";
+        let password = SafeCell::new(PASSWORD.to_vec());
+        let password2 = SafeCell::new(PASSWORD.to_vec());
+        let salt = generate_salt();
+
+        let mut key1 = derive_key(password, &salt);
+        let mut key2 = derive_key(password2, &salt);
+
+        let key1_reader = key1.0.read();
+        let key2_reader = key2.0.read();
+
+        assert_eq!(key1_reader.deref(), key2_reader.deref());
+    }
+
+    #[test]
+    pub fn successful_derive() {
+        static PASSWORD: &[u8] = b"password";
+        let password = SafeCell::new(PASSWORD.to_vec());
+        let salt = generate_salt();
+
+        let mut key = derive_key(password, &salt);
+        let key_reader = key.0.read();
+        let key_ref = key_reader.deref();
+
+        assert_ne!(key_ref.as_slice(), &[0u8; 32][..]);
+    }
+
+    #[test]
+    // We should fuzz this
+    pub fn test_nonce_increment() {
+        let mut nonce = Nonce([0u8; NONCE_LENGTH]);
+        nonce.increment();
+
+        assert_eq!(
+            nonce.0,
+            [
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
+            ]
+        );
+    }
+}

server/crates/arbiter-server/src/crypto/integrity/mod.rs

@@ -0,0 +1 @@
+pub mod v1;

server/crates/arbiter-server/src/crypto/integrity/v1.rs

@@ -0,0 +1,78 @@
+use crate::{crypto::KeyCell, safe_cell::SafeCellHandle as _};
+use chacha20poly1305::Key;
+use hmac::Mac as _;
+
+pub const USERAGENT_INTEGRITY_DERIVE_TAG: &[u8] = "arbiter/useragent/integrity-key/v1".as_bytes();
+pub const USERAGENT_INTEGRITY_TAG: &[u8] = "arbiter/useragent/pubkey-entry/v1".as_bytes();
+
+/// Computes an integrity tag for a specific domain and payload shape.
+pub fn compute_integrity_tag<'a, I>(
+    integrity_key: &mut KeyCell,
+    purpose_tag: &[u8],
+    data_parts: I,
+) -> [u8; 32]
+where
+    I: IntoIterator<Item = &'a [u8]>,
+{
+    type HmacSha256 = hmac::Hmac<sha2::Sha256>;
+
+    let mut output_tag = [0u8; 32];
+    integrity_key.0.read_inline(|integrity_key_bytes: &Key| {
+        let mut mac = <HmacSha256 as hmac::Mac>::new_from_slice(integrity_key_bytes.as_ref())
+            .expect("HMAC key initialization must not fail for 32-byte key");
+        mac.update(purpose_tag);
+        for data_part in data_parts {
+            mac.update(data_part);
+        }
+        output_tag.copy_from_slice(&mac.finalize().into_bytes());
+    });
+
+    output_tag
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        crypto::{derive_key, encryption::v1::generate_salt},
+        safe_cell::{SafeCell, SafeCellHandle as _},
+    };
+
+    use super::{USERAGENT_INTEGRITY_TAG, compute_integrity_tag};
+
+    #[test]
+    pub fn integrity_tag_deterministic() {
+        let salt = generate_salt();
+        let mut integrity_key = derive_key(SafeCell::new(b"password".to_vec()), &salt);
+        let key_type = 1i32.to_be_bytes();
+        let t1 = compute_integrity_tag(
+            &mut integrity_key,
+            USERAGENT_INTEGRITY_TAG,
+            [key_type.as_slice(), b"pubkey".as_ref()],
+        );
+        let t2 = compute_integrity_tag(
+            &mut integrity_key,
+            USERAGENT_INTEGRITY_TAG,
+            [key_type.as_slice(), b"pubkey".as_ref()],
+        );
+        assert_eq!(t1, t2);
+    }
+
+    #[test]
+    pub fn integrity_tag_changes_with_payload() {
+        let salt = generate_salt();
+        let mut integrity_key = derive_key(SafeCell::new(b"password".to_vec()), &salt);
+        let key_type_1 = 1i32.to_be_bytes();
+        let key_type_2 = 2i32.to_be_bytes();
+        let t1 = compute_integrity_tag(
+            &mut integrity_key,
+            USERAGENT_INTEGRITY_TAG,
+            [key_type_1.as_slice(), b"pubkey".as_ref()],
+        );
+        let t2 = compute_integrity_tag(
+            &mut integrity_key,
+            USERAGENT_INTEGRITY_TAG,
+            [key_type_2.as_slice(), b"pubkey".as_ref()],
+        );
+        assert_ne!(t1, t2);
+    }
+}

server/crates/arbiter-server/src/crypto/mod.rs

@@ -0,0 +1,159 @@
+use std::ops::Deref as _;
+
+use argon2::{Algorithm, Argon2};
+use chacha20poly1305::{
+    AeadInPlace, Key, KeyInit as _, XChaCha20Poly1305, XNonce,
+    aead::{AeadMut, Error, Payload},
+};
+use rand::{
+    Rng as _, SeedableRng as _,
+    rngs::{StdRng, SysRng},
+};
+
+use crate::safe_cell::{SafeCell, SafeCellHandle as _};
+
+pub mod encryption;
+pub mod integrity;
+
+use encryption::v1::{Nonce, Salt};
+
+pub struct KeyCell(pub SafeCell<Key>);
+impl From<SafeCell<Key>> for KeyCell {
+    fn from(value: SafeCell<Key>) -> Self {
+        Self(value)
+    }
+}
+impl TryFrom<SafeCell<Vec<u8>>> for KeyCell {
+    type Error = ();
+
+    fn try_from(mut value: SafeCell<Vec<u8>>) -> Result<Self, Self::Error> {
+        let value = value.read();
+        if value.len() != size_of::<Key>() {
+            return Err(());
+        }
+        let cell = SafeCell::new_inline(|cell_write: &mut Key| {
+            cell_write.copy_from_slice(&value);
+        });
+        Ok(Self(cell))
+    }
+}
+
+impl KeyCell {
+    pub fn new_secure_random() -> Self {
+        let key = SafeCell::new_inline(|key_buffer: &mut Key| {
+            #[allow(
+                clippy::unwrap_used,
+                reason = "Rng failure is unrecoverable and should panic"
+            )]
+            let mut rng = StdRng::try_from_rng(&mut SysRng).unwrap();
+            rng.fill_bytes(key_buffer);
+        });
+
+        key.into()
+    }
+
+    pub fn encrypt_in_place(
+        &mut self,
+        nonce: &Nonce,
+        associated_data: &[u8],
+        mut buffer: impl AsMut<Vec<u8>>,
+    ) -> Result<(), Error> {
+        let key_reader = self.0.read();
+        let key_ref = key_reader.deref();
+        let cipher = XChaCha20Poly1305::new(key_ref);
+        let nonce = XNonce::from_slice(nonce.0.as_ref());
+        let buffer = buffer.as_mut();
+        cipher.encrypt_in_place(nonce, associated_data, buffer)
+    }
+    pub fn decrypt_in_place(
+        &mut self,
+        nonce: &Nonce,
+        associated_data: &[u8],
+        buffer: &mut SafeCell<Vec<u8>>,
+    ) -> Result<(), Error> {
+        let key_reader = self.0.read();
+        let key_ref = key_reader.deref();
+        let cipher = XChaCha20Poly1305::new(key_ref);
+        let nonce = XNonce::from_slice(nonce.0.as_ref());
+        let mut buffer = buffer.write();
+        let buffer: &mut Vec<u8> = buffer.as_mut();
+        cipher.decrypt_in_place(nonce, associated_data, buffer)
+    }
+
+    pub fn encrypt(
+        &mut self,
+        nonce: &Nonce,
+        associated_data: &[u8],
+        plaintext: impl AsRef<[u8]>,
+    ) -> Result<Vec<u8>, Error> {
+        let key_reader = self.0.read();
+        let key_ref = key_reader.deref();
+        let mut cipher = XChaCha20Poly1305::new(key_ref);
+        let nonce = XNonce::from_slice(nonce.0.as_ref());
+
+        let ciphertext = cipher.encrypt(
+            nonce,
+            Payload {
+                msg: plaintext.as_ref(),
+                aad: associated_data,
+            },
+        )?;
+        Ok(ciphertext)
+    }
+}
+
+/// User password might be of different length, have not enough entropy, etc...
+/// Derive a fixed-length key from the password using Argon2id, which is designed for password hashing and key derivation.
+pub fn derive_key(mut password: SafeCell<Vec<u8>>, salt: &Salt) -> KeyCell {
+    #[allow(clippy::unwrap_used)]
+    let params = argon2::Params::new(262_144, 3, 4, None).unwrap();
+    let hasher = Argon2::new(Algorithm::Argon2id, argon2::Version::V0x13, params);
+    let mut key = SafeCell::new(Key::default());
+    password.read_inline(|password_source| {
+        let mut key_buffer = key.write();
+        let key_buffer: &mut [u8] = key_buffer.as_mut();
+
+        #[allow(
+            clippy::unwrap_used,
+            reason = "Better fail completely than return a weak key"
+        )]
+        hasher
+            .hash_password_into(password_source.deref(), salt, key_buffer)
+            .unwrap();
+    });
+
+    key.into()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{
+        derive_key,
+        encryption::v1::{Nonce, generate_salt},
+    };
+    use crate::safe_cell::{SafeCell, SafeCellHandle as _};
+
+    #[test]
+    pub fn encrypt_decrypt() {
+        static PASSWORD: &[u8] = b"password";
+        let password = SafeCell::new(PASSWORD.to_vec());
+        let salt = generate_salt();
+
+        let mut key = derive_key(password, &salt);
+        let nonce = Nonce(*b"unique nonce 123 1231233"); // 24 bytes for XChaCha20Poly1305
+        let associated_data = b"associated data";
+        let mut buffer = b"secret data".to_vec();
+
+        key.encrypt_in_place(&nonce, associated_data, &mut buffer)
+            .unwrap();
+        assert_ne!(buffer, b"secret data");
+
+        let mut buffer = SafeCell::new(buffer);
+
+        key.decrypt_in_place(&nonce, associated_data, &mut buffer)
+            .unwrap();
+
+        let buffer = buffer.read();
+        assert_eq!(*buffer, b"secret data");
+    }
+}

server/crates/arbiter-server/src/db/mod.rs

@@ -5,7 +5,7 @@ use diesel_async::{
     sync_connection_wrapper::SyncConnectionWrapper,
 };
 use diesel_migrations::{EmbeddedMigrations, MigrationHarness, embed_migrations};
-use miette::Diagnostic;
+
 use thiserror::Error;
 use tracing::info;
 
@@ -21,29 +21,32 @@ static DB_FILE: &str = "arbiter.sqlite";
 
 const MIGRATIONS: EmbeddedMigrations = embed_migrations!("migrations");
 
-#[derive(Error, Diagnostic, Debug)]
+#[derive(Error, Debug)]
 pub enum DatabaseSetupError {
     #[error("Failed to determine home directory")]
-    #[diagnostic(code(arbiter::db::home_dir))]
     HomeDir(std::io::Error),
 
     #[error(transparent)]
-    #[diagnostic(code(arbiter::db::connection))]
     Connection(diesel::ConnectionError),
 
     #[error(transparent)]
-    #[diagnostic(code(arbiter::db::concurrency))]
     ConcurrencySetup(diesel::result::Error),
 
     #[error(transparent)]
-    #[diagnostic(code(arbiter::db::migration))]
     Migration(Box<dyn std::error::Error + Send + Sync>),
 
     #[error(transparent)]
-    #[diagnostic(code(arbiter::db::pool))]
     Pool(#[from] PoolInitError),
 }
 
+#[derive(Error, Debug)]
+pub enum DatabaseError {
+    #[error("Database connection error")]
+    Pool(#[from] PoolError),
+    #[error("Database query error")]
+    Connection(#[from] diesel::result::Error),
+}
+
 #[tracing::instrument(level = "info")]
 fn database_path() -> Result<std::path::PathBuf, DatabaseSetupError> {
     let arbiter_home = arbiter_proto::home_path().map_err(DatabaseSetupError::HomeDir)?;
@@ -92,6 +95,7 @@ fn initialize_database(url: &str) -> Result<(), DatabaseSetupError> {
 #[tracing::instrument(level = "info")]
 pub async fn create_pool(url: Option<&str>) -> Result<DatabasePool, DatabaseSetupError> {
     let database_url = url.map(String::from).unwrap_or(
+        #[allow(clippy::expect_used)]
         database_path()?
             .to_str()
             .expect("database path is not valid UTF-8")
@@ -135,11 +139,13 @@ pub async fn create_test_pool() -> DatabasePool {
     let tempfile_name = Alphanumeric.sample_string(&mut rand::rng(), 16);
 
     let file = std::env::temp_dir().join(tempfile_name);
+    #[allow(clippy::expect_used)]
     let url = file
         .to_str()
         .expect("temp file path is not valid UTF-8")
         .to_string();
 
+    #[allow(clippy::expect_used)]
     create_pool(Some(&url))
         .await
         .expect("Failed to create test database pool")

server/crates/arbiter-server/src/db/models.rs

@@ -21,7 +21,7 @@ pub mod types {
         sqlite::{Sqlite, SqliteType},
     };
 
-    #[derive(Debug, FromSqlRow, AsExpression)]
+    #[derive(Debug, FromSqlRow, AsExpression, Clone)]
     #[diesel(sql_type = Integer)]
     #[repr(transparent)] // hint compiler to optimize the wrapper struct away
     pub struct SqliteTimestamp(pub DateTime<Utc>);
@@ -185,12 +185,53 @@ pub struct EvmWallet {
     pub created_at: SqliteTimestamp,
 }
 
-#[derive(Queryable, Debug, Insertable, Selectable)]
+#[derive(Models, Queryable, Debug, Insertable, Selectable, Clone)]
+#[diesel(table_name = schema::evm_wallet_access, check_for_backend(Sqlite))]
+#[view(
+    NewEvmWalletAccess,
+    derive(Insertable),
+    omit(id, created_at),
+    attributes_with = "deriveless"
+)]
+#[view(
+    CoreEvmWalletAccess,
+    derive(Insertable),
+    omit(created_at),
+    attributes_with = "deriveless"
+)]
+pub struct EvmWalletAccess {
+    pub id: i32,
+    pub wallet_id: i32,
+    pub client_id: i32,
+    pub created_at: SqliteTimestamp,
+}
+
+#[derive(Models, Queryable, Debug, Insertable, Selectable)]
+#[diesel(table_name = schema::client_metadata, check_for_backend(Sqlite))]
+pub struct ProgramClientMetadata {
+    pub id: i32,
+    pub name: String,
+    pub description: Option<String>,
+    pub version: Option<String>,
+    pub created_at: SqliteTimestamp,
+}
+
+#[derive(Models, Queryable, Debug, Insertable, Selectable)]
+#[diesel(table_name = schema::client_metadata_history, check_for_backend(Sqlite))]
+pub struct ProgramClientMetadataHistory {
+    pub id: i32,
+    pub metadata_id: i32,
+    pub client_id: i32,
+    pub created_at: SqliteTimestamp,
+}
+
+#[derive(Models, Queryable, Debug, Insertable, Selectable)]
 #[diesel(table_name = schema::program_client, check_for_backend(Sqlite))]
 pub struct ProgramClient {
     pub id: i32,
     pub nonce: i32,
     pub public_key: Vec<u8>,
+    pub metadata_id: i32,
     pub created_at: SqliteTimestamp,
     pub updated_at: SqliteTimestamp,
 }
@@ -201,6 +242,7 @@ pub struct UseragentClient {
     pub id: i32,
     pub nonce: i32,
     pub public_key: Vec<u8>,
+    pub pubkey_integrity_tag: Option<Vec<u8>>,
     pub created_at: SqliteTimestamp,
     pub updated_at: SqliteTimestamp,
     pub key_type: KeyType,
@@ -230,8 +272,7 @@ pub struct EvmEtherTransferLimit {
 )]
 pub struct EvmBasicGrant {
     pub id: i32,
-    pub wallet_id: i32, // references evm_wallet.id
+    pub wallet_access_id: i32, // references evm_wallet_access.id
-    pub client_id: i32, // references program_client.id
     pub chain_id: i32,
     pub valid_from: Option<SqliteTimestamp>,
     pub valid_until: Option<SqliteTimestamp>,
@@ -254,8 +295,7 @@ pub struct EvmBasicGrant {
 pub struct EvmTransactionLog {
     pub id: i32,
     pub grant_id: i32,
-    pub client_id: i32,
+    pub wallet_access_id: i32,
-    pub wallet_id: i32,
     pub chain_id: i32,
     pub eth_value: Vec<u8>,
     pub signed_at: SqliteTimestamp,

server/crates/arbiter-server/src/db/schema.rs

@@ -20,11 +20,29 @@ diesel::table! {
     }
 }
 
+diesel::table! {
+    client_metadata (id) {
+        id -> Integer,
+        name -> Text,
+        description -> Nullable<Text>,
+        version -> Nullable<Text>,
+        created_at -> Integer,
+    }
+}
+
+diesel::table! {
+    client_metadata_history (id) {
+        id -> Integer,
+        metadata_id -> Integer,
+        client_id -> Integer,
+        created_at -> Integer,
+    }
+}
+
 diesel::table! {
     evm_basic_grant (id) {
         id -> Integer,
-        wallet_id -> Integer,
+        wallet_access_id -> Integer,
-        client_id -> Integer,
         chain_id -> Integer,
         valid_from -> Nullable<Integer>,
         valid_until -> Nullable<Integer>,
@@ -95,9 +113,8 @@ diesel::table! {
 diesel::table! {
     evm_transaction_log (id) {
         id -> Integer,
+        wallet_access_id -> Integer,
         grant_id -> Integer,
-        client_id -> Integer,
-        wallet_id -> Integer,
         chain_id -> Integer,
         eth_value -> Binary,
         signed_at -> Integer,
@@ -113,11 +130,21 @@ diesel::table! {
     }
 }
 
+diesel::table! {
+    evm_wallet_access (id) {
+        id -> Integer,
+        wallet_id -> Integer,
+        client_id -> Integer,
+        created_at -> Integer,
+    }
+}
+
 diesel::table! {
     program_client (id) {
         id -> Integer,
         nonce -> Integer,
         public_key -> Binary,
+        metadata_id -> Integer,
         created_at -> Integer,
         updated_at -> Integer,
     }
@@ -151,17 +178,19 @@ diesel::table! {
         id -> Integer,
         nonce -> Integer,
         public_key -> Binary,
+        pubkey_integrity_tag -> Nullable<Binary>,
+        key_type -> Integer,
         created_at -> Integer,
         updated_at -> Integer,
-        key_type -> Integer,
     }
 }
 
 diesel::joinable!(aead_encrypted -> root_key_history (associated_root_key_id));
 diesel::joinable!(arbiter_settings -> root_key_history (root_key_id));
 diesel::joinable!(arbiter_settings -> tls_history (tls_id));
-diesel::joinable!(evm_basic_grant -> evm_wallet (wallet_id));
+diesel::joinable!(client_metadata_history -> client_metadata (metadata_id));
-diesel::joinable!(evm_basic_grant -> program_client (client_id));
+diesel::joinable!(client_metadata_history -> program_client (client_id));
+diesel::joinable!(evm_basic_grant -> evm_wallet_access (wallet_access_id));
 diesel::joinable!(evm_ether_transfer_grant -> evm_basic_grant (basic_grant_id));
 diesel::joinable!(evm_ether_transfer_grant -> evm_ether_transfer_limit (limit_id));
 diesel::joinable!(evm_ether_transfer_grant_target -> evm_ether_transfer_grant (grant_id));
@@ -169,11 +198,18 @@ diesel::joinable!(evm_token_transfer_grant -> evm_basic_grant (basic_grant_id));
 diesel::joinable!(evm_token_transfer_log -> evm_token_transfer_grant (grant_id));
 diesel::joinable!(evm_token_transfer_log -> evm_transaction_log (log_id));
 diesel::joinable!(evm_token_transfer_volume_limit -> evm_token_transfer_grant (grant_id));
+diesel::joinable!(evm_transaction_log -> evm_basic_grant (grant_id));
+diesel::joinable!(evm_transaction_log -> evm_wallet_access (wallet_access_id));
 diesel::joinable!(evm_wallet -> aead_encrypted (aead_encrypted_id));
+diesel::joinable!(evm_wallet_access -> evm_wallet (wallet_id));
+diesel::joinable!(evm_wallet_access -> program_client (client_id));
+diesel::joinable!(program_client -> client_metadata (metadata_id));
 
 diesel::allow_tables_to_appear_in_same_query!(
     aead_encrypted,
     arbiter_settings,
+    client_metadata,
+    client_metadata_history,
     evm_basic_grant,
     evm_ether_transfer_grant,
     evm_ether_transfer_grant_target,
@@ -183,6 +219,7 @@ diesel::allow_tables_to_appear_in_same_query!(
     evm_token_transfer_volume_limit,
     evm_transaction_log,
     evm_wallet,
+    evm_wallet_access,
     program_client,
     root_key_history,
     tls_history,

server/crates/arbiter-server/src/evm/mod.rs

@@ -6,13 +6,15 @@ use alloy::{
     primitives::{TxKind, U256},
 };
 use chrono::Utc;
-use diesel::{ExpressionMethods as _, QueryDsl, QueryResult, insert_into, sqlite::Sqlite};
+use diesel::{ExpressionMethods as _, QueryDsl as _, QueryResult, insert_into, sqlite::Sqlite};
 use diesel_async::{AsyncConnection, RunQueryDsl};
 
 use crate::{
     db::{
-        self,
+        self, DatabaseError,
-        models::{EvmBasicGrant, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp},
+        models::{
+            EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp,
+        },
         schema::{self, evm_transaction_log},
     },
     evm::policies::{
@@ -26,78 +28,35 @@ pub mod policies;
 mod utils;
 
 /// Errors that can only occur once the transaction meaning is known (during policy evaluation)
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
+#[derive(Debug, thiserror::Error)]
 pub enum PolicyError {
-    #[error("Database connection pool error")]
+    #[error("Database error")]
-    #[diagnostic(code(arbiter_server::evm::policy_error::pool))]
+    Database(#[from] crate::db::DatabaseError),
-    Pool(#[from] db::PoolError),
-    #[error("Database returned error")]
-    #[diagnostic(code(arbiter_server::evm::policy_error::database))]
-    Database(#[from] diesel::result::Error),
     #[error("Transaction violates policy: {0:?}")]
-    #[diagnostic(code(arbiter_server::evm::policy_error::violation))]
     Violations(Vec<EvalViolation>),
     #[error("No matching grant found")]
-    #[diagnostic(code(arbiter_server::evm::policy_error::no_matching_grant))]
     NoMatchingGrant,
 }
 
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
+#[derive(Debug, thiserror::Error)]
 pub enum VetError {
     #[error("Contract creation transactions are not supported")]
-    #[diagnostic(code(arbiter_server::evm::vet_error::contract_creation_unsupported))]
     ContractCreationNotSupported,
     #[error("Engine can't classify this transaction")]
-    #[diagnostic(code(arbiter_server::evm::vet_error::unsupported))]
     UnsupportedTransactionType,
     #[error("Policy evaluation failed: {1}")]
-    #[diagnostic(code(arbiter_server::evm::vet_error::evaluated))]
     Evaluated(SpecificMeaning, #[source] PolicyError),
 }
 
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
+#[derive(Debug, thiserror::Error)]
-pub enum SignError {
-    #[error("Database connection pool error")]
-    #[diagnostic(code(arbiter_server::evm::database_error))]
-    Pool(#[from] db::PoolError),
-    #[error("Database returned error")]
-    #[diagnostic(code(arbiter_server::evm::database_error))]
-    Database(#[from] diesel::result::Error),
-}
-
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
 pub enum AnalyzeError {
     #[error("Engine doesn't support granting permissions for contract creation")]
-    #[diagnostic(code(arbiter_server::evm::analyze_error::contract_creation_not_supported))]
     ContractCreationNotSupported,
 
     #[error("Unsupported transaction type")]
-    #[diagnostic(code(arbiter_server::evm::analyze_error::unsupported_transaction_type))]
     UnsupportedTransactionType,
 }
 
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
-pub enum CreationError {
-    #[error("Database connection pool error")]
-    #[diagnostic(code(arbiter_server::evm::creation_error::database_error))]
-    Pool(#[from] db::PoolError),
-
-    #[error("Database returned error")]
-    #[diagnostic(code(arbiter_server::evm::creation_error::database_error))]
-    Database(#[from] diesel::result::Error),
-}
-
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
-pub enum ListGrantsError {
-    #[error("Database connection pool error")]
-    #[diagnostic(code(arbiter_server::evm::list_grants_error::pool))]
-    Pool(#[from] db::PoolError),
-
-    #[error("Database returned error")]
-    #[diagnostic(code(arbiter_server::evm::list_grants_error::database))]
-    Database(#[from] diesel::result::Error),
-}
-
 /// Controls whether a transaction should be executed or only validated
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum RunKind {
@@ -117,9 +76,7 @@ async fn check_shared_constraints(
     let now = Utc::now();
 
     // Validity window
-    if shared.valid_from.is_some_and(|t| now < t)
+    if shared.valid_from.is_some_and(|t| now < t) || shared.valid_until.is_some_and(|t| now > t) {
-        || shared.valid_until.is_some_and(|t| now > t)
-    {
         violations.push(EvalViolation::InvalidTime);
     }
 
@@ -127,9 +84,9 @@ async fn check_shared_constraints(
     let fee_exceeded = shared
         .max_gas_fee_per_gas
         .is_some_and(|cap| U256::from(context.max_fee_per_gas) > cap);
-    let priority_exceeded = shared.max_priority_fee_per_gas.is_some_and(|cap| {
+    let priority_exceeded = shared
-        U256::from(context.max_priority_fee_per_gas) > cap
+        .max_priority_fee_per_gas
-    });
+        .is_some_and(|cap| U256::from(context.max_priority_fee_per_gas) > cap);
     if fee_exceeded || priority_exceeded {
         violations.push(EvalViolation::GasLimitExceeded {
             max_gas_fee_per_gas: shared.max_gas_fee_per_gas,
@@ -167,16 +124,22 @@ impl Engine {
         meaning: &P::Meaning,
         run_kind: RunKind,
     ) -> Result<(), PolicyError> {
-        let mut conn = self.db.get().await?;
+        let mut conn = self.db.get().await.map_err(DatabaseError::from)?;
 
         let grant = P::try_find_grant(&context, &mut conn)
-            .await?
+            .await
+            .map_err(DatabaseError::from)?
             .ok_or(PolicyError::NoMatchingGrant)?;
 
         let mut violations =
             check_shared_constraints(&context, &grant.shared, grant.shared_grant_id, &mut conn)
-                .await?;
+                .await
-        violations.extend(P::evaluate(&context, meaning, &grant, &mut conn).await?);
+                .map_err(DatabaseError::from)?;
+        violations.extend(
+            P::evaluate(&context, meaning, &grant, &mut conn)
+                .await
+                .map_err(DatabaseError::from)?,
+        );
 
         if !violations.is_empty() {
             return Err(PolicyError::Violations(violations));
@@ -186,8 +149,7 @@ impl Engine {
                     let log_id: i32 = insert_into(evm_transaction_log::table)
                         .values(&NewEvmTransactionLog {
                             grant_id: grant.shared_grant_id,
-                            client_id: context.client_id,
+                            wallet_access_id: context.target.id,
-                            wallet_id: context.wallet_id,
                             chain_id: context.chain as i32,
                             eth_value: utils::u256_to_bytes(context.value).to_vec(),
                             signed_at: Utc::now().into(),
@@ -201,7 +163,8 @@ impl Engine {
                     QueryResult::Ok(())
                 })
             })
-            .await?;
+            .await
+            .map_err(DatabaseError::from)?;
         }
 
         Ok(())
@@ -215,9 +178,8 @@ impl Engine {
 
     pub async fn create_grant<P: Policy>(
         &self,
-        client_id: i32,
         full_grant: FullGrant<P::Settings>,
-    ) -> Result<i32, CreationError> {
+    ) -> Result<i32, DatabaseError> {
         let mut conn = self.db.get().await?;
 
         let id = conn
@@ -227,9 +189,8 @@ impl Engine {
 
                     let basic_grant: EvmBasicGrant = insert_into(evm_basic_grant::table)
                         .values(&NewEvmBasicGrant {
-                            wallet_id: full_grant.basic.wallet_id,
                             chain_id: full_grant.basic.chain as i32,
-                            client_id,
+                            wallet_access_id: full_grant.basic.wallet_access_id,
                             valid_from: full_grant.basic.valid_from.map(SqliteTimestamp),
                             valid_until: full_grant.basic.valid_until.map(SqliteTimestamp),
                             max_gas_fee_per_gas: full_grant
@@ -264,7 +225,7 @@ impl Engine {
         Ok(id)
     }
 
-    pub async fn list_all_grants(&self) -> Result<Vec<Grant<SpecificGrant>>, ListGrantsError> {
+    pub async fn list_all_grants(&self) -> Result<Vec<Grant<SpecificGrant>>, DatabaseError> {
         let mut conn = self.db.get().await?;
 
         let mut grants: Vec<Grant<SpecificGrant>> = Vec::new();
@@ -297,8 +258,7 @@ impl Engine {
 
     pub async fn evaluate_transaction(
         &self,
-        wallet_id: i32,
+        target: EvmWalletAccess,
-        client_id: i32,
         transaction: TxEip1559,
         run_kind: RunKind,
     ) -> Result<SpecificMeaning, VetError> {
@@ -306,8 +266,7 @@ impl Engine {
             return Err(VetError::ContractCreationNotSupported);
         };
         let context = policies::EvalContext {
-            wallet_id,
+            target,
-            client_id,
             chain: transaction.chain_id,
             to,
             value: transaction.value,

server/crates/arbiter-server/src/evm/policies.rs

@@ -6,11 +6,11 @@ use diesel::{
     ExpressionMethods as _, QueryDsl, SelectableHelper, result::QueryResult, sqlite::Sqlite,
 };
 use diesel_async::{AsyncConnection, RunQueryDsl};
-use miette::Diagnostic;
+
 use thiserror::Error;
 
 use crate::{
-    db::models::{self, EvmBasicGrant},
+    db::models::{self, EvmBasicGrant, EvmWalletAccess},
     evm::utils,
 };
 
@@ -19,9 +19,8 @@ pub mod token_transfers;
 
 #[derive(Debug, Clone)]
 pub struct EvalContext {
-    // Which wallet is this transaction for
+    // Which wallet is this transaction for and who requested it
-    pub client_id: i32,
+    pub target: EvmWalletAccess,
-    pub wallet_id: i32,
 
     // The transaction data
     pub chain: ChainId,
@@ -34,38 +33,33 @@ pub struct EvalContext {
     pub max_priority_fee_per_gas: u128,
 }
 
-#[derive(Debug, Error, Diagnostic)]
+#[derive(Debug, Error)]
 pub enum EvalViolation {
     #[error("This grant doesn't allow transactions to the target address {target}")]
-    #[diagnostic(code(arbiter_server::evm::eval_violation::invalid_target))]
     InvalidTarget { target: Address },
 
     #[error("Gas limit exceeded for this grant")]
-    #[diagnostic(code(arbiter_server::evm::eval_violation::gas_limit_exceeded))]
     GasLimitExceeded {
         max_gas_fee_per_gas: Option<U256>,
         max_priority_fee_per_gas: Option<U256>,
     },
 
     #[error("Rate limit exceeded for this grant")]
-    #[diagnostic(code(arbiter_server::evm::eval_violation::rate_limit_exceeded))]
     RateLimitExceeded,
 
     #[error("Transaction exceeds volumetric limits of the grant")]
-    #[diagnostic(code(arbiter_server::evm::eval_violation::volumetric_limit_exceeded))]
     VolumetricLimitExceeded,
 
     #[error("Transaction is outside of the grant's validity period")]
-    #[diagnostic(code(arbiter_server::evm::eval_violation::invalid_time))]
     InvalidTime,
 
     #[error("Transaction type is not allowed by this grant")]
-    #[diagnostic(code(arbiter_server::evm::eval_violation::invalid_transaction_type))]
     InvalidTransactionType,
 }
 
 pub type DatabaseID = i32;
 
+#[derive(Debug)]
 pub struct Grant<PolicySettings> {
     pub id: DatabaseID,
     pub shared_grant_id: DatabaseID, // ID of the basic grant for shared-logic checks like rate limits and validity periods
@@ -73,7 +67,6 @@ pub struct Grant<PolicySettings> {
     pub settings: PolicySettings,
 }
 
-
 pub trait Policy: Sized {
     type Settings: Send + Sync + 'static + Into<SpecificGrant>;
     type Meaning: Display + std::fmt::Debug + Send + Sync + 'static + Into<SpecificMeaning>;
@@ -145,7 +138,7 @@ pub struct VolumeRateLimit {
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct SharedGrantSettings {
-    pub wallet_id: i32,
+    pub wallet_access_id: i32,
     pub chain: ChainId,
 
     pub valid_from: Option<DateTime<Utc>>,
@@ -160,7 +153,7 @@ pub struct SharedGrantSettings {
 impl SharedGrantSettings {
     fn try_from_model(model: EvmBasicGrant) -> QueryResult<Self> {
         Ok(Self {
-            wallet_id: model.wallet_id,
+            wallet_access_id: model.wallet_access_id,
             chain: model.chain_id as u64, // safe because chain_id is stored as i32 but is guaranteed to be a valid ChainId by the API when creating grants
             valid_from: model.valid_from.map(Into::into),
             valid_until: model.valid_until.map(Into::into),
@@ -198,6 +191,7 @@ impl SharedGrantSettings {
     }
 }
 
+#[derive(Debug, Clone)]
 pub enum SpecificGrant {
     EtherTransfer(ether_transfer::Settings),
     TokenTransfer(token_transfers::Settings),

server/crates/arbiter-server/src/evm/policies/ether_transfer/mod.rs

@@ -36,8 +36,8 @@ use super::{DatabaseID, EvalContext, EvalViolation};
 // Plain ether transfer
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Meaning {
-    to: Address,
+    pub(crate) to: Address,
-    value: U256,
+    pub(crate) value: U256,
 }
 impl Display for Meaning {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -51,9 +51,10 @@ impl From<Meaning> for SpecificMeaning {
 }
 
 // A grant for ether transfers, which can be scoped to specific target addresses and volume limits
+#[derive(Debug, Clone)]
 pub struct Settings {
-    target: Vec<Address>,
+    pub target: Vec<Address>,
-    limit: VolumeRateLimit,
+    pub limit: VolumeRateLimit,
 }
 
 impl From<Settings> for SpecificGrant {
@@ -90,6 +91,7 @@ async fn query_relevant_past_transaction(
 
 async fn check_rate_limits(
     grant: &Grant<Settings>,
+    current_transfer_value: U256,
     db: &mut impl AsyncConnection<Backend = Sqlite>,
 ) -> QueryResult<Vec<EvalViolation>> {
     let mut violations = Vec::new();
@@ -98,12 +100,12 @@ async fn check_rate_limits(
     let past_transaction = query_relevant_past_transaction(grant.id, window, db).await?;
 
     let window_start = chrono::Utc::now() - grant.settings.limit.window;
-    let cumulative_volume: U256 = past_transaction
+    let prospective_cumulative_volume: U256 = past_transaction
         .iter()
         .filter(|(_, timestamp)| timestamp >= &window_start)
-        .fold(U256::default(), |acc, (value, _)| acc + *value);
+        .fold(current_transfer_value, |acc, (value, _)| acc + *value);
 
-    if cumulative_volume > grant.settings.limit.max_volume {
+    if prospective_cumulative_volume > grant.settings.limit.max_volume {
         violations.push(EvalViolation::VolumetricLimitExceeded);
     }
 
@@ -140,7 +142,7 @@ impl Policy for EtherTransfer {
             violations.push(EvalViolation::InvalidTarget { target: meaning.to });
         }
 
-        let rate_violations = check_rate_limits(grant, db).await?;
+        let rate_violations = check_rate_limits(grant, meaning.value, db).await?;
         violations.extend(rate_violations);
 
         Ok(violations)
@@ -195,9 +197,8 @@ impl Policy for EtherTransfer {
             .inner_join(evm_basic_grant::table)
             .inner_join(evm_ether_transfer_grant_target::table)
             .filter(
-                evm_basic_grant::wallet_id
+                evm_basic_grant::wallet_access_id
-                    .eq(context.wallet_id)
+                    .eq(context.target.id)
-                    .and(evm_basic_grant::client_id.eq(context.client_id))
                     .and(evm_basic_grant::revoked_at.is_null())
                     .and(evm_ether_transfer_grant_target::address.eq(&target_bytes)),
             )

server/crates/arbiter-server/src/evm/policies/ether_transfer/tests.rs

@@ -5,20 +5,19 @@ use diesel_async::RunQueryDsl;
 
 use crate::db::{
     self, DatabaseConnection,
-    models::{EvmBasicGrant, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp},
+    models::{
+        EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, NewEvmTransactionLog, SqliteTimestamp,
+    },
     schema::{evm_basic_grant, evm_transaction_log},
 };
 use crate::evm::{
-    policies::{
+    policies::{EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit},
-        EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit,
-    },
     utils,
 };
 
 use super::{EtherTransfer, Settings};
 
-const WALLET_ID: i32 = 1;
+const WALLET_ACCESS_ID: i32 = 1;
-const CLIENT_ID: i32 = 2;
 const CHAIN_ID: u64 = 1;
 
 const ALLOWED: Address = address!("1111111111111111111111111111111111111111");
@@ -26,8 +25,12 @@ const OTHER: Address = address!("2222222222222222222222222222222222222222");
 
 fn ctx(to: Address, value: U256) -> EvalContext {
     EvalContext {
-        wallet_id: WALLET_ID,
+        target: EvmWalletAccess {
-        client_id: CLIENT_ID,
+            id: WALLET_ACCESS_ID,
+            wallet_id: 10,
+            client_id: 20,
+            created_at: SqliteTimestamp(Utc::now()),
+        },
         chain: CHAIN_ID,
         to,
         value,
@@ -40,8 +43,7 @@ fn ctx(to: Address, value: U256) -> EvalContext {
 async fn insert_basic(conn: &mut DatabaseConnection, revoked: bool) -> EvmBasicGrant {
     insert_into(evm_basic_grant::table)
         .values(NewEvmBasicGrant {
-            wallet_id: WALLET_ID,
+            wallet_access_id: WALLET_ACCESS_ID,
-            client_id: CLIENT_ID,
             chain_id: CHAIN_ID as i32,
             valid_from: None,
             valid_until: None,
@@ -69,7 +71,7 @@ fn make_settings(targets: Vec<Address>, max_volume: u64) -> Settings {
 
 fn shared() -> SharedGrantSettings {
     SharedGrantSettings {
-        wallet_id: WALLET_ID,
+        wallet_access_id: WALLET_ACCESS_ID,
         chain: CHAIN_ID,
         valid_from: None,
         valid_until: None,
@@ -154,8 +156,7 @@ async fn evaluate_passes_when_volume_within_limit() {
     insert_into(evm_transaction_log::table)
         .values(NewEvmTransactionLog {
             grant_id,
-            client_id: CLIENT_ID,
+            wallet_access_id: WALLET_ACCESS_ID,
-            wallet_id: WALLET_ID,
             chain_id: CHAIN_ID as i32,
             eth_value: utils::u256_to_bytes(U256::from(500u64)).to_vec(),
             signed_at: SqliteTimestamp(Utc::now()),
@@ -195,10 +196,9 @@ async fn evaluate_rejects_volume_over_limit() {
     insert_into(evm_transaction_log::table)
         .values(NewEvmTransactionLog {
             grant_id,
-            client_id: CLIENT_ID,
+            wallet_access_id: WALLET_ACCESS_ID,
-            wallet_id: WALLET_ID,
             chain_id: CHAIN_ID as i32,
-            eth_value: utils::u256_to_bytes(U256::from(1_001u64)).to_vec(),
+            eth_value: utils::u256_to_bytes(U256::from(1_000u64)).to_vec(),
             signed_at: SqliteTimestamp(Utc::now()),
         })
         .execute(&mut *conn)
@@ -211,7 +211,7 @@ async fn evaluate_rejects_volume_over_limit() {
         shared: shared(),
         settings,
     };
-    let context = ctx(ALLOWED, U256::from(100u64));
+    let context = ctx(ALLOWED, U256::from(1u64));
     let m = EtherTransfer::analyze(&context).unwrap();
     let v = EtherTransfer::evaluate(&context, &m, &grant, &mut *conn)
         .await
@@ -233,14 +233,13 @@ async fn evaluate_passes_at_exactly_volume_limit() {
         .await
         .unwrap();
 
-    // Exactly at the limit — the check is `>`, so this should not violate
+    // Exactly at the limit including current transfer — check is `>`, so this should not violate
     insert_into(evm_transaction_log::table)
         .values(NewEvmTransactionLog {
             grant_id,
-            client_id: CLIENT_ID,
+            wallet_access_id: WALLET_ACCESS_ID,
-            wallet_id: WALLET_ID,
             chain_id: CHAIN_ID as i32,
-            eth_value: utils::u256_to_bytes(U256::from(1_000u64)).to_vec(),
+            eth_value: utils::u256_to_bytes(U256::from(900u64)).to_vec(),
             signed_at: SqliteTimestamp(Utc::now()),
         })
         .execute(&mut *conn)

server/crates/arbiter-server/src/evm/policies/token_transfers/mod.rs

@@ -38,9 +38,9 @@ fn grant_join() -> _ {
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Meaning {
-    token: &'static TokenInfo,
+    pub(crate) token: &'static TokenInfo,
-    to: Address,
+    pub(crate) to: Address,
-    value: U256,
+    pub(crate) value: U256,
 }
 impl std::fmt::Display for Meaning {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -58,10 +58,11 @@ impl From<Meaning> for SpecificMeaning {
 }
 
 // A grant for token transfers, which can be scoped to specific target addresses and volume limits
+#[derive(Debug, Clone)]
 pub struct Settings {
-    token_contract: Address,
+    pub token_contract: Address,
-    target: Option<Address>,
+    pub target: Option<Address>,
-    volume_limits: Vec<VolumeRateLimit>,
+    pub volume_limits: Vec<VolumeRateLimit>,
 }
 impl From<Settings> for SpecificGrant {
     fn from(val: Settings) -> SpecificGrant {
@@ -100,6 +101,7 @@ async fn query_relevant_past_transfers(
 
 async fn check_volume_rate_limits(
     grant: &Grant<Settings>,
+    current_transfer_value: U256,
     db: &mut impl AsyncConnection<Backend = Sqlite>,
 ) -> QueryResult<Vec<EvalViolation>> {
     let mut violations = Vec::new();
@@ -112,12 +114,12 @@ async fn check_volume_rate_limits(
 
     for limit in &grant.settings.volume_limits {
         let window_start = chrono::Utc::now() - limit.window;
-        let cumulative_volume: U256 = past_transfers
+        let prospective_cumulative_volume: U256 = past_transfers
             .iter()
             .filter(|(_, timestamp)| timestamp >= &window_start)
-            .fold(U256::default(), |acc, (value, _)| acc + *value);
+            .fold(current_transfer_value, |acc, (value, _)| acc + *value);
 
-        if cumulative_volume > limit.max_volume {
+        if prospective_cumulative_volume > limit.max_volume {
             violations.push(EvalViolation::VolumetricLimitExceeded);
             break;
         }
@@ -162,7 +164,7 @@ impl Policy for TokenTransfer {
             violations.push(EvalViolation::InvalidTarget { target: meaning.to });
         }
 
-        let rate_violations = check_volume_rate_limits(grant, db).await?;
+        let rate_violations = check_volume_rate_limits(grant, meaning.value, db).await?;
         violations.extend(rate_violations);
 
         Ok(violations)
@@ -208,8 +210,7 @@ impl Policy for TokenTransfer {
 
         let grant: Option<(EvmBasicGrant, EvmTokenTransferGrant)> = grant_join()
             .filter(evm_basic_grant::revoked_at.is_null())
-            .filter(evm_basic_grant::wallet_id.eq(context.wallet_id))
+            .filter(evm_basic_grant::wallet_access_id.eq(context.target.id))
-            .filter(evm_basic_grant::client_id.eq(context.client_id))
             .filter(evm_token_transfer_grant::token_contract.eq(&token_contract_bytes))
             .select((
                 EvmBasicGrant::as_select(),

server/crates/arbiter-server/src/evm/policies/token_transfers/tests.rs

@@ -6,7 +6,7 @@ use diesel_async::RunQueryDsl;
 
 use crate::db::{
     self, DatabaseConnection,
-    models::{EvmBasicGrant, NewEvmBasicGrant, SqliteTimestamp},
+    models::{EvmBasicGrant, EvmWalletAccess, NewEvmBasicGrant, SqliteTimestamp},
     schema::evm_basic_grant,
 };
 use crate::evm::{
@@ -21,8 +21,7 @@ use super::{Settings, TokenTransfer};
 const CHAIN_ID: u64 = 1;
 const DAI: Address = address!("6B175474E89094C44Da98b954EedeAC495271d0F");
 
-const WALLET_ID: i32 = 1;
+const WALLET_ACCESS_ID: i32 = 1;
-const CLIENT_ID: i32 = 2;
 
 const RECIPIENT: Address = address!("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
 const OTHER: Address = address!("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb");
@@ -38,8 +37,12 @@ fn transfer_calldata(to: Address, value: U256) -> Bytes {
 
 fn ctx(to: Address, calldata: Bytes) -> EvalContext {
     EvalContext {
-        wallet_id: WALLET_ID,
+        target: EvmWalletAccess {
-        client_id: CLIENT_ID,
+            id: WALLET_ACCESS_ID,
+            wallet_id: 10,
+            client_id: 20,
+            created_at: SqliteTimestamp(Utc::now()),
+        },
         chain: CHAIN_ID,
         to,
         value: U256::ZERO,
@@ -52,8 +55,7 @@ fn ctx(to: Address, calldata: Bytes) -> EvalContext {
 async fn insert_basic(conn: &mut DatabaseConnection, revoked: bool) -> EvmBasicGrant {
     insert_into(evm_basic_grant::table)
         .values(NewEvmBasicGrant {
-            wallet_id: WALLET_ID,
+            wallet_access_id: WALLET_ACCESS_ID,
-            client_id: CLIENT_ID,
             chain_id: CHAIN_ID as i32,
             valid_from: None,
             valid_until: None,
@@ -86,7 +88,7 @@ fn make_settings(target: Option<Address>, max_volume: Option<u64>) -> Settings {
 
 fn shared() -> SharedGrantSettings {
     SharedGrantSettings {
-        wallet_id: WALLET_ID,
+        wallet_access_id: WALLET_ACCESS_ID,
         chain: CHAIN_ID,
         valid_from: None,
         valid_until: None,
@@ -140,10 +142,18 @@ async fn evaluate_rejects_nonzero_eth_value() {
     let mut context = ctx(DAI, calldata);
     context.value = U256::from(1u64); // ETH attached to an ERC-20 call
 
-    let m = TokenTransfer::analyze(&EvalContext { value: U256::ZERO, ..context.clone() })
+    let m = TokenTransfer::analyze(&EvalContext {
+        value: U256::ZERO,
+        ..context.clone()
+    })
     .unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
-    assert!(v.iter().any(|e| matches!(e, EvalViolation::InvalidTransactionType)));
+        .await
+        .unwrap();
+    assert!(
+        v.iter()
+            .any(|e| matches!(e, EvalViolation::InvalidTransactionType))
+    );
 }
 
 #[tokio::test]
@@ -160,7 +170,9 @@ async fn evaluate_passes_any_recipient_when_no_restriction() {
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
+        .await
+        .unwrap();
     assert!(v.is_empty());
 }
 
@@ -178,7 +190,9 @@ async fn evaluate_passes_matching_restricted_recipient() {
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
+        .await
+        .unwrap();
     assert!(v.is_empty());
 }
 
@@ -196,20 +210,27 @@ async fn evaluate_rejects_wrong_restricted_recipient() {
     let calldata = transfer_calldata(OTHER, U256::from(100u64));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
-    assert!(v.iter().any(|e| matches!(e, EvalViolation::InvalidTarget { .. })));
+        .await
+        .unwrap();
+    assert!(
+        v.iter()
+            .any(|e| matches!(e, EvalViolation::InvalidTarget { .. }))
+    );
 }
 
 #[tokio::test]
-async fn evaluate_passes_volume_within_limit() {
+async fn evaluate_passes_volume_at_exact_limit() {
     let db = db::create_test_pool().await;
     let mut conn = db.get().await.unwrap();
 
     let basic = insert_basic(&mut conn, false).await;
     let settings = make_settings(None, Some(1_000));
-    let grant_id = TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    let grant_id = TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
-    // Record a past transfer of 500 (within 1000 limit)
+    // Record a past transfer of 900, with current transfer 100 => exactly 1000 limit
     use crate::db::{models::NewEvmTokenTransferLog, schema::evm_token_transfer_log};
     insert_into(evm_token_transfer_log::table)
         .values(NewEvmTokenTransferLog {
@@ -218,18 +239,28 @@ async fn evaluate_passes_volume_within_limit() {
             chain_id: CHAIN_ID as i32,
             token_contract: DAI.to_vec(),
             recipient_address: RECIPIENT.to_vec(),
-            value: utils::u256_to_bytes(U256::from(500u64)).to_vec(),
+            value: utils::u256_to_bytes(U256::from(900u64)).to_vec(),
         })
         .execute(&mut *conn)
         .await
         .unwrap();
 
-    let grant = Grant { id: grant_id, shared_grant_id: basic.id, shared: shared(), settings };
+    let grant = Grant {
+        id: grant_id,
+        shared_grant_id: basic.id,
+        shared: shared(),
+        settings,
+    };
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
-    assert!(!v.iter().any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded)));
+        .await
+        .unwrap();
+    assert!(
+        !v.iter()
+            .any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded))
+    );
 }
 
 #[tokio::test]
@@ -239,7 +270,9 @@ async fn evaluate_rejects_volume_over_limit() {
 
     let basic = insert_basic(&mut conn, false).await;
     let settings = make_settings(None, Some(1_000));
-    let grant_id = TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    let grant_id = TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     use crate::db::{models::NewEvmTokenTransferLog, schema::evm_token_transfer_log};
     insert_into(evm_token_transfer_log::table)
@@ -249,18 +282,28 @@ async fn evaluate_rejects_volume_over_limit() {
             chain_id: CHAIN_ID as i32,
             token_contract: DAI.to_vec(),
             recipient_address: RECIPIENT.to_vec(),
-            value: utils::u256_to_bytes(U256::from(1_001u64)).to_vec(),
+            value: utils::u256_to_bytes(U256::from(1_000u64)).to_vec(),
         })
         .execute(&mut *conn)
         .await
         .unwrap();
 
-    let grant = Grant { id: grant_id, shared_grant_id: basic.id, shared: shared(), settings };
+    let grant = Grant {
-    let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
+        id: grant_id,
+        shared_grant_id: basic.id,
+        shared: shared(),
+        settings,
+    };
+    let calldata = transfer_calldata(RECIPIENT, U256::from(1u64));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
-    assert!(v.iter().any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded)));
+        .await
+        .unwrap();
+    assert!(
+        v.iter()
+            .any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded))
+    );
 }
 
 #[tokio::test]
@@ -277,8 +320,13 @@ async fn evaluate_no_volume_limits_always_passes() {
     let calldata = transfer_calldata(RECIPIENT, U256::from(u64::MAX));
     let context = ctx(DAI, calldata);
     let m = TokenTransfer::analyze(&context).unwrap();
-    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn).await.unwrap();
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
-    assert!(!v.iter().any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded)));
+        .await
+        .unwrap();
+    assert!(
+        !v.iter()
+            .any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded))
+    );
 }
 
 // ── try_find_grant ───────────────────────────────────────────────────────
@@ -290,7 +338,9 @@ async fn try_find_grant_roundtrip() {
 
     let basic = insert_basic(&mut conn, false).await;
     let settings = make_settings(Some(RECIPIENT), Some(5_000));
-    TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     let calldata = transfer_calldata(RECIPIENT, U256::from(100u64));
     let found = TokenTransfer::try_find_grant(&ctx(DAI, calldata), &mut *conn)
@@ -312,7 +362,9 @@ async fn try_find_grant_revoked_returns_none() {
 
     let basic = insert_basic(&mut conn, true).await;
     let settings = make_settings(None, None);
-    TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     let calldata = transfer_calldata(RECIPIENT, U256::from(1u64));
     let found = TokenTransfer::try_find_grant(&ctx(DAI, calldata), &mut *conn)
@@ -328,7 +380,9 @@ async fn try_find_grant_unknown_token_returns_none() {
 
     let basic = insert_basic(&mut conn, false).await;
     let settings = make_settings(None, None);
-    TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     // Query with a different token contract
     let calldata = transfer_calldata(RECIPIENT, U256::from(1u64));
@@ -355,9 +409,13 @@ async fn find_all_grants_excludes_revoked() {
 
     let settings = make_settings(None, Some(1_000));
     let active = insert_basic(&mut conn, false).await;
-    TokenTransfer::create_grant(&active, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&active, &settings, &mut *conn)
+        .await
+        .unwrap();
     let revoked = insert_basic(&mut conn, true).await;
-    TokenTransfer::create_grant(&revoked, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&revoked, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     let all = TokenTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
@@ -370,12 +428,17 @@ async fn find_all_grants_loads_volume_limits() {
 
     let basic = insert_basic(&mut conn, false).await;
     let settings = make_settings(None, Some(9_999));
-    TokenTransfer::create_grant(&basic, &settings, &mut *conn).await.unwrap();
+    TokenTransfer::create_grant(&basic, &settings, &mut *conn)
+        .await
+        .unwrap();
 
     let all = TokenTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 1);
     assert_eq!(all[0].settings.volume_limits.len(), 1);
-    assert_eq!(all[0].settings.volume_limits[0].max_volume, U256::from(9_999u64));
+    assert_eq!(
+        all[0].settings.volume_limits[0].max_volume,
+        U256::from(9_999u64)
+    );
 }
 
 #[tokio::test]
@@ -388,7 +451,11 @@ async fn find_all_grants_multiple_grants_batch_loaded() {
         .await
         .unwrap();
     let b2 = insert_basic(&mut conn, false).await;
-    TokenTransfer::create_grant(&b2, &make_settings(Some(RECIPIENT), Some(2_000)), &mut *conn)
+    TokenTransfer::create_grant(
+        &b2,
+        &make_settings(Some(RECIPIENT), Some(2_000)),
+        &mut *conn,
+    )
     .await
     .unwrap();
 

server/crates/arbiter-server/src/evm/safe_signer.rs

@@ -1,14 +1,14 @@
 use std::sync::Mutex;
 
+use crate::safe_cell::{SafeCell, SafeCellHandle as _};
 use alloy::{
     consensus::SignableTransaction,
     network::{TxSigner, TxSignerSync},
-    primitives::{Address, ChainId, Signature, B256},
+    primitives::{Address, B256, ChainId, Signature},
     signers::{Error, Result, Signer, SignerSync, utils::secret_key_to_address},
 };
 use async_trait::async_trait;
-use k256::ecdsa::{self, signature::hazmat::PrehashSigner, RecoveryId, SigningKey};
+use k256::ecdsa::{self, RecoveryId, SigningKey, signature::hazmat::PrehashSigner};
-use memsafe::MemSafe;
 
 /// An Ethereum signer that stores its secp256k1 secret key inside a
 /// hardware-protected [`MemSafe`] cell.
@@ -20,7 +20,7 @@ use memsafe::MemSafe;
 /// Because [`MemSafe::read`] requires `&mut self` while the [`Signer`] trait
 /// requires `&self`, the cell is wrapped in a [`Mutex`].
 pub struct SafeSigner {
-    key: Mutex<MemSafe<SigningKey>>,
+    key: Mutex<SafeCell<SigningKey>>,
     address: Address,
     chain_id: Option<ChainId>,
 }
@@ -42,14 +42,13 @@ impl std::fmt::Debug for SafeSigner {
 /// rejection, but we retry to be correct).
 ///
 /// Returns the protected key bytes and the derived Ethereum address.
-pub fn generate(rng: &mut impl rand::Rng) -> (MemSafe<[u8; 32]>, Address) {
+pub fn generate(rng: &mut impl rand::Rng) -> (SafeCell<[u8; 32]>, Address) {
     loop {
-        let mut cell = MemSafe::new([0u8; 32]).expect("MemSafe allocation");
+        let mut cell = SafeCell::new_inline(|w: &mut [u8; 32]| {
-        {
+            rng.fill_bytes(w);
-            let mut w = cell.write().expect("MemSafe write");
+        });
-            rng.fill_bytes(w.as_mut());
+
-        }
+        let reader = cell.read();
-        let reader = cell.read().expect("MemSafe read");
         if let Ok(sk) = SigningKey::from_slice(reader.as_ref()) {
             let address = secret_key_to_address(&sk);
             drop(reader);
@@ -64,8 +63,8 @@ impl SafeSigner {
     /// The key bytes are read from protected memory, parsed as a secp256k1
     /// scalar, and immediately moved into a new [`MemSafe`] cell. The raw
     /// bytes are never exposed outside this function.
-    pub fn from_memsafe(mut cell: MemSafe<Vec<u8>>) -> Result<Self> {
+    pub fn from_cell(mut cell: SafeCell<Vec<u8>>) -> Result<Self> {
-        let reader = cell.read().map_err(Error::other)?;
+        let reader = cell.read();
         let sk = SigningKey::from_slice(reader.as_slice()).map_err(Error::other)?;
         drop(reader);
         Self::new(sk)
@@ -75,7 +74,7 @@ impl SafeSigner {
     /// memory region.
     pub fn new(key: SigningKey) -> Result<Self> {
         let address = secret_key_to_address(&key);
-        let cell = MemSafe::new(key).map_err(Error::other)?;
+        let cell = SafeCell::new(key);
         Ok(Self {
             key: Mutex::new(cell),
             address,
@@ -84,25 +83,25 @@ impl SafeSigner {
     }
 
     fn sign_hash_inner(&self, hash: &B256) -> Result<Signature> {
+        #[allow(clippy::expect_used)]
         let mut cell = self.key.lock().expect("SafeSigner mutex poisoned");
-        let reader = cell.read().map_err(Error::other)?;
+        let reader = cell.read();
         let sig: (ecdsa::Signature, RecoveryId) = reader.sign_prehash(hash.as_ref())?;
         Ok(sig.into())
     }
 
-    fn sign_tx_inner(
+    fn sign_tx_inner(&self, tx: &mut dyn SignableTransaction<Signature>) -> Result<Signature> {
-        &self,
-        tx: &mut dyn SignableTransaction<Signature>,
-    ) -> Result<Signature> {
         if let Some(chain_id) = self.chain_id
             && !tx.set_chain_id_checked(chain_id)
         {
             return Err(Error::TransactionChainIdMismatch {
                 signer: chain_id,
-                tx: tx.chain_id().unwrap(),
+                #[allow(clippy::expect_used)]
+                tx: tx.chain_id().expect("Chain ID is guaranteed to be set"),
             });
         }
-        self.sign_hash_inner(&tx.signature_hash()).map_err(Error::other)
+        self.sign_hash_inner(&tx.signature_hash())
+            .map_err(Error::other)
     }
 }
 

server/crates/arbiter-server/src/grpc/client.rs

@@ -0,0 +1,116 @@
+use arbiter_proto::{
+    proto::client::{
+        ClientRequest, ClientResponse, client_request::Payload as ClientRequestPayload,
+        client_response::Payload as ClientResponsePayload,
+    },
+    transport::{Receiver, Sender, grpc::GrpcBi},
+};
+use kameo::actor::{ActorRef, Spawn as _};
+use tonic::Status;
+use tracing::{info, warn};
+
+use crate::{
+    actors::client::{ClientConnection, session::ClientSession},
+    grpc::request_tracker::RequestTracker,
+};
+
+mod auth;
+mod evm;
+mod inbound;
+mod outbound;
+mod vault;
+
+async fn dispatch_loop(
+    mut bi: GrpcBi<ClientRequest, ClientResponse>,
+    actor: ActorRef<ClientSession>,
+    mut request_tracker: RequestTracker,
+) {
+    loop {
+        let Some(message) = bi.recv().await else {
+            return;
+        };
+
+        let conn = match message {
+            Ok(conn) => conn,
+            Err(err) => {
+                warn!(error = ?err, "Failed to receive client request");
+                return;
+            }
+        };
+
+        let request_id = match request_tracker.request(conn.request_id) {
+            Ok(id) => id,
+            Err(err) => {
+                let _ = bi.send(Err(err)).await;
+                return;
+            }
+        };
+
+        let Some(payload) = conn.payload else {
+            let _ = bi
+                .send(Err(Status::invalid_argument(
+                    "Missing client request payload",
+                )))
+                .await;
+            return;
+        };
+
+        match dispatch_inner(&actor, payload).await {
+            Ok(response) => {
+                if bi
+                    .send(Ok(ClientResponse {
+                        request_id: Some(request_id),
+                        payload: Some(response),
+                    }))
+                    .await
+                    .is_err()
+                {
+                    return;
+                }
+            }
+            Err(status) => {
+                let _ = bi.send(Err(status)).await;
+                return;
+            }
+        }
+    }
+}
+
+async fn dispatch_inner(
+    actor: &ActorRef<ClientSession>,
+    payload: ClientRequestPayload,
+) -> Result<ClientResponsePayload, Status> {
+    match payload {
+        ClientRequestPayload::Vault(req) => vault::dispatch(actor, req).await,
+        ClientRequestPayload::Evm(req) => evm::dispatch(actor, req).await,
+        ClientRequestPayload::Auth(..) => {
+            warn!("Unsupported post-auth client auth request");
+            Err(Status::invalid_argument("Unsupported client request"))
+        }
+    }
+}
+
+pub async fn start(mut conn: ClientConnection, mut bi: GrpcBi<ClientRequest, ClientResponse>) {
+    let mut request_tracker = RequestTracker::default();
+
+    let client_id = match auth::start(&mut conn, &mut bi, &mut request_tracker).await {
+        Ok(id) => id,
+        Err(err) => {
+            let _ = bi
+                .send(Err(Status::unauthenticated(format!(
+                    "Authentication failed: {}",
+                    err
+                ))))
+                .await;
+            warn!(error = ?err, "Client authentication failed");
+            return;
+        }
+    };
+
+    let actor = ClientSession::spawn(ClientSession::new(conn, client_id));
+    let actor_for_cleanup = actor.clone();
+
+    info!("Client authenticated successfully");
+    dispatch_loop(bi, actor, request_tracker).await;
+    actor_for_cleanup.kill();
+}

server/crates/arbiter-server/src/grpc/client/auth.rs

@@ -0,0 +1,205 @@
+use arbiter_proto::{
+    ClientMetadata,
+    proto::{
+        client::{
+            ClientRequest, ClientResponse,
+            auth::{
+                self as proto_auth, AuthChallenge as ProtoAuthChallenge,
+                AuthChallengeRequest as ProtoAuthChallengeRequest,
+                AuthChallengeSolution as ProtoAuthChallengeSolution, AuthResult as ProtoAuthResult,
+                request::Payload as AuthRequestPayload, response::Payload as AuthResponsePayload,
+            },
+            client_request::Payload as ClientRequestPayload,
+            client_response::Payload as ClientResponsePayload,
+        },
+        shared::ClientInfo as ProtoClientInfo,
+    },
+    transport::{Bi, Error as TransportError, Receiver, Sender, grpc::GrpcBi},
+};
+use async_trait::async_trait;
+use tonic::Status;
+use tracing::warn;
+
+use crate::{
+    actors::client::{self, ClientConnection, auth},
+    grpc::request_tracker::RequestTracker,
+};
+
+pub struct AuthTransportAdapter<'a> {
+    bi: &'a mut GrpcBi<ClientRequest, ClientResponse>,
+    request_tracker: &'a mut RequestTracker,
+}
+
+impl<'a> AuthTransportAdapter<'a> {
+    pub fn new(
+        bi: &'a mut GrpcBi<ClientRequest, ClientResponse>,
+        request_tracker: &'a mut RequestTracker,
+    ) -> Self {
+        Self {
+            bi,
+            request_tracker,
+        }
+    }
+
+    fn response_to_proto(response: auth::Outbound) -> AuthResponsePayload {
+        match response {
+            auth::Outbound::AuthChallenge { pubkey, nonce } => {
+                AuthResponsePayload::Challenge(ProtoAuthChallenge {
+                    pubkey: pubkey.to_bytes().to_vec(),
+                    nonce,
+                })
+            }
+            auth::Outbound::AuthSuccess => {
+                AuthResponsePayload::Result(ProtoAuthResult::Success.into())
+            }
+        }
+    }
+
+    fn error_to_proto(error: auth::Error) -> AuthResponsePayload {
+        AuthResponsePayload::Result(
+            match error {
+                auth::Error::InvalidChallengeSolution => ProtoAuthResult::InvalidSignature,
+                auth::Error::ApproveError(auth::ApproveError::Denied) => {
+                    ProtoAuthResult::ApprovalDenied
+                }
+                auth::Error::ApproveError(auth::ApproveError::Upstream(
+                    crate::actors::flow_coordinator::ApprovalError::NoUserAgentsConnected,
+                )) => ProtoAuthResult::NoUserAgentsOnline,
+                auth::Error::ApproveError(auth::ApproveError::Internal)
+                | auth::Error::DatabasePoolUnavailable
+                | auth::Error::DatabaseOperationFailed
+                | auth::Error::Transport => ProtoAuthResult::Internal,
+            }
+            .into(),
+        )
+    }
+
+    async fn send_client_response(
+        &mut self,
+        payload: AuthResponsePayload,
+    ) -> Result<(), TransportError> {
+        self.bi
+            .send(Ok(ClientResponse {
+                request_id: Some(self.request_tracker.current_request_id()),
+                payload: Some(ClientResponsePayload::Auth(proto_auth::Response {
+                    payload: Some(payload),
+                })),
+            }))
+            .await
+    }
+
+    async fn send_auth_result(&mut self, result: ProtoAuthResult) -> Result<(), TransportError> {
+        self.send_client_response(AuthResponsePayload::Result(result.into()))
+            .await
+    }
+}
+
+#[async_trait]
+impl Sender<Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {
+    async fn send(
+        &mut self,
+        item: Result<auth::Outbound, auth::Error>,
+    ) -> Result<(), TransportError> {
+        let payload = match item {
+            Ok(message) => AuthTransportAdapter::response_to_proto(message),
+            Err(err) => AuthTransportAdapter::error_to_proto(err),
+        };
+
+        self.send_client_response(payload).await
+    }
+}
+
+#[async_trait]
+impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
+    async fn recv(&mut self) -> Option<auth::Inbound> {
+        let request = match self.bi.recv().await? {
+            Ok(request) => request,
+            Err(error) => {
+                warn!(error = ?error, "grpc client recv failed; closing stream");
+                return None;
+            }
+        };
+
+        match self.request_tracker.request(request.request_id) {
+            Ok(request_id) => request_id,
+            Err(error) => {
+                let _ = self.bi.send(Err(error)).await;
+                return None;
+            }
+        };
+        let payload = request.payload?;
+        let ClientRequestPayload::Auth(auth_request) = payload else {
+            let _ = self
+                .bi
+                .send(Err(Status::invalid_argument(
+                    "Unsupported client auth request",
+                )))
+                .await;
+            return None;
+        };
+        let Some(payload) = auth_request.payload else {
+            let _ = self
+                .bi
+                .send(Err(Status::invalid_argument(
+                    "Missing client auth request payload",
+                )))
+                .await;
+            return None;
+        };
+
+        match payload {
+            AuthRequestPayload::ChallengeRequest(ProtoAuthChallengeRequest {
+                pubkey,
+                client_info,
+            }) => {
+                let Some(client_info) = client_info else {
+                    let _ = self
+                        .bi
+                        .send(Err(Status::invalid_argument("Missing client info")))
+                        .await;
+                    return None;
+                };
+                let Ok(pubkey) = <[u8; 32]>::try_from(pubkey) else {
+                    let _ = self.send_auth_result(ProtoAuthResult::InvalidKey).await;
+                    return None;
+                };
+                let Ok(pubkey) = ed25519_dalek::VerifyingKey::from_bytes(&pubkey) else {
+                    let _ = self.send_auth_result(ProtoAuthResult::InvalidKey).await;
+                    return None;
+                };
+                Some(auth::Inbound::AuthChallengeRequest {
+                    pubkey,
+                    metadata: client_metadata_from_proto(client_info),
+                })
+            }
+            AuthRequestPayload::ChallengeSolution(ProtoAuthChallengeSolution { signature }) => {
+                let Ok(signature) = ed25519_dalek::Signature::try_from(signature.as_slice()) else {
+                    let _ = self
+                        .send_auth_result(ProtoAuthResult::InvalidSignature)
+                        .await;
+                    return None;
+                };
+                Some(auth::Inbound::AuthChallengeSolution { signature })
+            }
+        }
+    }
+}
+
+impl Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {}
+
+fn client_metadata_from_proto(metadata: ProtoClientInfo) -> ClientMetadata {
+    ClientMetadata {
+        name: metadata.name,
+        description: metadata.description,
+        version: metadata.version,
+    }
+}
+
+pub async fn start(
+    conn: &mut ClientConnection,
+    bi: &mut GrpcBi<ClientRequest, ClientResponse>,
+    request_tracker: &mut RequestTracker,
+) -> Result<i32, auth::Error> {
+    let mut transport = AuthTransportAdapter::new(bi, request_tracker);
+    client::auth::authenticate(conn, &mut transport).await
+}

server/crates/arbiter-server/src/grpc/client/evm.rs

@@ -0,0 +1,87 @@
+use arbiter_proto::proto::{
+    client::{
+        client_response::Payload as ClientResponsePayload,
+        evm::{
+            self as proto_evm, request::Payload as EvmRequestPayload,
+            response::Payload as EvmResponsePayload,
+        },
+    },
+    evm::{
+        EvmError as ProtoEvmError, EvmSignTransactionResponse,
+        evm_sign_transaction_response::Result as EvmSignTransactionResult,
+    },
+};
+use kameo::actor::ActorRef;
+use tonic::Status;
+use tracing::warn;
+
+use crate::{
+    actors::client::session::{ClientSession, HandleSignTransaction, SignTransactionRpcError},
+    grpc::{
+        Convert, TryConvert,
+        common::inbound::{RawEvmAddress, RawEvmTransaction},
+    },
+};
+
+fn wrap_response(payload: EvmResponsePayload) -> ClientResponsePayload {
+    ClientResponsePayload::Evm(proto_evm::Response {
+        payload: Some(payload),
+    })
+}
+
+pub(super) async fn dispatch(
+    actor: &ActorRef<ClientSession>,
+    req: proto_evm::Request,
+) -> Result<ClientResponsePayload, Status> {
+    let Some(payload) = req.payload else {
+        return Err(Status::invalid_argument(
+            "Missing client EVM request payload",
+        ));
+    };
+
+    match payload {
+        EvmRequestPayload::SignTransaction(request) => {
+            let address = RawEvmAddress(request.wallet_address).try_convert()?;
+            let transaction = RawEvmTransaction(request.rlp_transaction).try_convert()?;
+
+            let response = match actor
+                .ask(HandleSignTransaction {
+                    wallet_address: address,
+                    transaction,
+                })
+                .await
+            {
+                Ok(signature) => EvmSignTransactionResponse {
+                    result: Some(EvmSignTransactionResult::Signature(
+                        signature.as_bytes().to_vec(),
+                    )),
+                },
+                Err(kameo::error::SendError::HandlerError(SignTransactionRpcError::Vet(
+                    vet_error,
+                ))) => EvmSignTransactionResponse {
+                    result: Some(vet_error.convert()),
+                },
+                Err(kameo::error::SendError::HandlerError(SignTransactionRpcError::Internal)) => {
+                    EvmSignTransactionResponse {
+                        result: Some(EvmSignTransactionResult::Error(
+                            ProtoEvmError::Internal.into(),
+                        )),
+                    }
+                }
+                Err(err) => {
+                    warn!(error = ?err, "Failed to sign EVM transaction");
+                    EvmSignTransactionResponse {
+                        result: Some(EvmSignTransactionResult::Error(
+                            ProtoEvmError::Internal.into(),
+                        )),
+                    }
+                }
+            };
+
+            Ok(wrap_response(EvmResponsePayload::SignTransaction(response)))
+        }
+        EvmRequestPayload::AnalyzeTransaction(_) => Err(Status::unimplemented(
+            "EVM transaction analysis is not yet implemented",
+        )),
+    }
+}

server/crates/arbiter-server/src/grpc/client/inbound.rs

@@ -0,0 +1 @@
+

server/crates/arbiter-server/src/grpc/client/outbound.rs

@@ -0,0 +1 @@
+

server/crates/arbiter-server/src/grpc/client/vault.rs

@@ -0,0 +1,47 @@
+use arbiter_proto::proto::{
+    client::{
+        client_response::Payload as ClientResponsePayload,
+        vault::{
+            self as proto_vault, request::Payload as VaultRequestPayload,
+            response::Payload as VaultResponsePayload,
+        },
+    },
+    shared::VaultState as ProtoVaultState,
+};
+use kameo::{actor::ActorRef, error::SendError};
+use tonic::Status;
+use tracing::warn;
+
+use crate::actors::{
+    client::session::{ClientSession, Error, HandleQueryVaultState},
+    keyholder::KeyHolderState,
+};
+
+pub(super) async fn dispatch(
+    actor: &ActorRef<ClientSession>,
+    req: proto_vault::Request,
+) -> Result<ClientResponsePayload, Status> {
+    let Some(payload) = req.payload else {
+        return Err(Status::invalid_argument(
+            "Missing client vault request payload",
+        ));
+    };
+
+    match payload {
+        VaultRequestPayload::QueryState(_) => {
+            let state = match actor.ask(HandleQueryVaultState {}).await {
+                Ok(KeyHolderState::Unbootstrapped) => ProtoVaultState::Unbootstrapped,
+                Ok(KeyHolderState::Sealed) => ProtoVaultState::Sealed,
+                Ok(KeyHolderState::Unsealed) => ProtoVaultState::Unsealed,
+                Err(SendError::HandlerError(Error::Internal)) => ProtoVaultState::Error,
+                Err(err) => {
+                    warn!(error = ?err, "Failed to query vault state");
+                    ProtoVaultState::Error
+                }
+            };
+            Ok(ClientResponsePayload::Vault(proto_vault::Response {
+                payload: Some(VaultResponsePayload::State(state.into())),
+            }))
+        }
+    }
+}

server/crates/arbiter-server/src/grpc/common.rs

@@ -0,0 +1,2 @@
+pub mod inbound;
+pub mod outbound;

server/crates/arbiter-server/src/grpc/common/inbound.rs

@@ -0,0 +1,35 @@
+use alloy::{consensus::TxEip1559, primitives::Address, rlp::Decodable as _};
+
+use crate::grpc::TryConvert;
+
+pub struct RawEvmAddress(pub Vec<u8>);
+impl TryConvert for RawEvmAddress {
+    type Output = Address;
+
+    type Error = tonic::Status;
+
+    fn try_convert(self) -> Result<Self::Output, Self::Error> {
+        let wallet_address = match <[u8; 20]>::try_from(self.0.as_slice()) {
+            Ok(address) => Address::from(address),
+            Err(_) => {
+                return Err(tonic::Status::invalid_argument(
+                    "Invalid EVM wallet address",
+                ));
+            }
+        };
+        Ok(wallet_address)
+    }
+}
+
+pub struct RawEvmTransaction(pub Vec<u8>);
+impl TryConvert for RawEvmTransaction {
+    type Output = TxEip1559;
+
+    type Error = tonic::Status;
+
+    fn try_convert(self) -> Result<Self::Output, Self::Error> {
+        let tx = TxEip1559::decode(&mut self.0.as_slice())
+            .map_err(|_| tonic::Status::invalid_argument("Invalid EVM transaction format"))?;
+        Ok(tx)
+    }
+}

server/crates/arbiter-server/src/grpc/common/outbound.rs

@@ -0,0 +1,119 @@
+use alloy::primitives::U256;
+use arbiter_proto::proto::{
+    evm::{
+        EvmError as ProtoEvmError,
+        evm_sign_transaction_response::Result as EvmSignTransactionResult,
+    },
+    shared::evm::{
+        EvalViolation as ProtoEvalViolation, GasLimitExceededViolation, NoMatchingGrantError,
+        PolicyViolationsError, SpecificMeaning as ProtoSpecificMeaning,
+        TokenInfo as ProtoTokenInfo, TransactionEvalError as ProtoTransactionEvalError,
+        eval_violation::Kind as ProtoEvalViolationKind,
+        specific_meaning::Meaning as ProtoSpecificMeaningKind,
+        transaction_eval_error::Kind as ProtoTransactionEvalErrorKind,
+    },
+};
+
+use crate::{
+    evm::{
+        PolicyError, VetError,
+        policies::{EvalViolation, SpecificMeaning},
+    },
+    grpc::Convert,
+};
+
+fn u256_to_proto_bytes(value: U256) -> Vec<u8> {
+    value.to_be_bytes::<32>().to_vec()
+}
+
+impl Convert for SpecificMeaning {
+    type Output = ProtoSpecificMeaning;
+
+    fn convert(self) -> Self::Output {
+        let kind = match self {
+            SpecificMeaning::EtherTransfer(meaning) => ProtoSpecificMeaningKind::EtherTransfer(
+                arbiter_proto::proto::shared::evm::EtherTransferMeaning {
+                    to: meaning.to.to_vec(),
+                    value: u256_to_proto_bytes(meaning.value),
+                },
+            ),
+            SpecificMeaning::TokenTransfer(meaning) => ProtoSpecificMeaningKind::TokenTransfer(
+                arbiter_proto::proto::shared::evm::TokenTransferMeaning {
+                    token: Some(ProtoTokenInfo {
+                        symbol: meaning.token.symbol.to_string(),
+                        address: meaning.token.contract.to_vec(),
+                        chain_id: meaning.token.chain,
+                    }),
+                    to: meaning.to.to_vec(),
+                    value: u256_to_proto_bytes(meaning.value),
+                },
+            ),
+        };
+
+        ProtoSpecificMeaning {
+            meaning: Some(kind),
+        }
+    }
+}
+
+impl Convert for EvalViolation {
+    type Output = ProtoEvalViolation;
+
+    fn convert(self) -> Self::Output {
+        let kind = match self {
+            EvalViolation::InvalidTarget { target } => {
+                ProtoEvalViolationKind::InvalidTarget(target.to_vec())
+            }
+            EvalViolation::GasLimitExceeded {
+                max_gas_fee_per_gas,
+                max_priority_fee_per_gas,
+            } => ProtoEvalViolationKind::GasLimitExceeded(GasLimitExceededViolation {
+                max_gas_fee_per_gas: max_gas_fee_per_gas.map(u256_to_proto_bytes),
+                max_priority_fee_per_gas: max_priority_fee_per_gas.map(u256_to_proto_bytes),
+            }),
+            EvalViolation::RateLimitExceeded => ProtoEvalViolationKind::RateLimitExceeded(()),
+            EvalViolation::VolumetricLimitExceeded => {
+                ProtoEvalViolationKind::VolumetricLimitExceeded(())
+            }
+            EvalViolation::InvalidTime => ProtoEvalViolationKind::InvalidTime(()),
+            EvalViolation::InvalidTransactionType => {
+                ProtoEvalViolationKind::InvalidTransactionType(())
+            }
+        };
+
+        ProtoEvalViolation { kind: Some(kind) }
+    }
+}
+
+impl Convert for VetError {
+    type Output = EvmSignTransactionResult;
+
+    fn convert(self) -> Self::Output {
+        let kind = match self {
+            VetError::ContractCreationNotSupported => {
+                ProtoTransactionEvalErrorKind::ContractCreationNotSupported(())
+            }
+            VetError::UnsupportedTransactionType => {
+                ProtoTransactionEvalErrorKind::UnsupportedTransactionType(())
+            }
+            VetError::Evaluated(meaning, policy_error) => match policy_error {
+                PolicyError::NoMatchingGrant => {
+                    ProtoTransactionEvalErrorKind::NoMatchingGrant(NoMatchingGrantError {
+                        meaning: Some(meaning.convert()),
+                    })
+                }
+                PolicyError::Violations(violations) => {
+                    ProtoTransactionEvalErrorKind::PolicyViolations(PolicyViolationsError {
+                        meaning: Some(meaning.convert()),
+                        violations: violations.into_iter().map(Convert::convert).collect(),
+                    })
+                }
+                PolicyError::Database(_) => {
+                    return EvmSignTransactionResult::Error(ProtoEvmError::Internal.into());
+                }
+            },
+        };
+
+        EvmSignTransactionResult::EvalError(ProtoTransactionEvalError { kind: Some(kind) }.into())
+    }
+}

server/crates/arbiter-server/src/grpc/mod.rs

@@ -0,0 +1,78 @@
+use arbiter_proto::{
+    proto::{
+        client::{ClientRequest, ClientResponse},
+        user_agent::{UserAgentRequest, UserAgentResponse},
+    },
+    transport::grpc::GrpcBi,
+};
+use tokio_stream::wrappers::ReceiverStream;
+use tonic::{Request, Response, Status, async_trait};
+use tracing::info;
+
+use crate::{
+    actors::{client::ClientConnection, user_agent::UserAgentConnection},
+    grpc::user_agent::start,
+};
+
+mod request_tracker;
+
+pub mod client;
+pub mod user_agent;
+
+mod common;
+
+pub trait Convert {
+    type Output;
+
+    fn convert(self) -> Self::Output;
+}
+
+pub trait TryConvert {
+    type Output;
+    type Error;
+
+    fn try_convert(self) -> Result<Self::Output, Self::Error>;
+}
+
+#[async_trait]
+impl arbiter_proto::proto::arbiter_service_server::ArbiterService for super::Server {
+    type UserAgentStream = ReceiverStream<Result<UserAgentResponse, Status>>;
+    type ClientStream = ReceiverStream<Result<ClientResponse, Status>>;
+
+    #[tracing::instrument(level = "debug", skip(self))]
+    async fn client(
+        &self,
+        request: Request<tonic::Streaming<ClientRequest>>,
+    ) -> Result<Response<Self::ClientStream>, Status> {
+        let req_stream = request.into_inner();
+        let (bi, rx) = GrpcBi::from_bi_stream(req_stream);
+        let props = ClientConnection::new(self.context.db.clone(), self.context.actors.clone());
+        tokio::spawn(client::start(props, bi));
+
+        info!(event = "connection established", "grpc.client");
+
+        Ok(Response::new(rx))
+    }
+
+    #[tracing::instrument(level = "debug", skip(self))]
+    async fn user_agent(
+        &self,
+        request: Request<tonic::Streaming<UserAgentRequest>>,
+    ) -> Result<Response<Self::UserAgentStream>, Status> {
+        let req_stream = request.into_inner();
+
+        let (bi, rx) = GrpcBi::from_bi_stream(req_stream);
+
+        tokio::spawn(start(
+            UserAgentConnection {
+                db: self.context.db.clone(),
+                actors: self.context.actors.clone(),
+            },
+            bi,
+        ));
+
+        info!(event = "connection established", "grpc.user_agent");
+
+        Ok(Response::new(rx))
+    }
+}

server/crates/arbiter-server/src/grpc/request_tracker.rs

@@ -0,0 +1,26 @@
+use tonic::Status;
+
+#[derive(Default)]
+pub struct RequestTracker {
+    next_request_id: i32,
+}
+
+impl RequestTracker {
+    pub fn request(&mut self, id: i32) -> Result<i32, Status> {
+        if id < self.next_request_id {
+            return Err(Status::invalid_argument("Duplicate request id"));
+        }
+
+        self.next_request_id = id
+            .checked_add(1)
+            .ok_or_else(|| Status::invalid_argument("Invalid request id"))?;
+
+        Ok(id)
+    }
+
+    // This is used to set the response id for auth responses, which need to match the request id of the auth challenge request.
+    // -1 offset is needed because request() increments the next_request_id after returning the current request id.
+    pub fn current_request_id(&self) -> i32 {
+        self.next_request_id - 1
+    }
+}

server/crates/arbiter-server/src/grpc/user_agent.rs

@@ -0,0 +1,144 @@
+use tokio::sync::mpsc;
+
+use arbiter_proto::{
+    proto::user_agent::{
+        UserAgentRequest, UserAgentResponse,
+        user_agent_request::Payload as UserAgentRequestPayload,
+        user_agent_response::Payload as UserAgentResponsePayload,
+    },
+    transport::{Error as TransportError, Receiver, Sender, grpc::GrpcBi},
+};
+use async_trait::async_trait;
+use kameo::actor::{ActorRef, Spawn as _};
+use tonic::Status;
+use tracing::{error, info, warn};
+
+use crate::{
+    actors::user_agent::{OutOfBand, UserAgentConnection, UserAgentSession},
+    grpc::request_tracker::RequestTracker,
+};
+
+mod auth;
+mod evm;
+mod inbound;
+mod outbound;
+mod sdk_client;
+mod vault;
+
+pub struct OutOfBandAdapter(mpsc::Sender<OutOfBand>);
+
+#[async_trait]
+impl Sender<OutOfBand> for OutOfBandAdapter {
+    async fn send(&mut self, item: OutOfBand) -> Result<(), TransportError> {
+        self.0.send(item).await.map_err(|e| {
+            warn!(error = ?e, "Failed to send out-of-band message");
+            TransportError::ChannelClosed
+        })
+    }
+}
+
+async fn dispatch_loop(
+    mut bi: GrpcBi<UserAgentRequest, UserAgentResponse>,
+    actor: ActorRef<UserAgentSession>,
+    mut receiver: mpsc::Receiver<OutOfBand>,
+    mut request_tracker: RequestTracker,
+) {
+    loop {
+        tokio::select! {
+            oob = receiver.recv() => {
+                let Some(oob) = oob else {
+                    warn!("Out-of-band message channel closed");
+                    return;
+                };
+
+                let payload = sdk_client::out_of_band_payload(oob);
+
+                if bi.send(Ok(UserAgentResponse { id: None, payload: Some(payload) })).await.is_err() {
+                    return;
+                }
+            }
+
+            message = bi.recv() => {
+                let Some(message) = message else { return; };
+
+                let conn = match message {
+                    Ok(conn) => conn,
+                    Err(err) => {
+                        warn!(error = ?err, "Failed to receive user agent request");
+                        return;
+                    }
+                };
+
+                let request_id = match request_tracker.request(conn.id) {
+                    Ok(id) => id,
+                    Err(err) => {
+                        let _ = bi.send(Err(err)).await;
+                        return;
+                    }
+                };
+
+                let Some(payload) = conn.payload else {
+                    let _ = bi.send(Err(Status::invalid_argument("Missing user-agent request payload"))).await;
+                    return;
+                };
+
+                match dispatch_inner(&actor, payload).await {
+                    Ok(Some(response)) => {
+                        if bi.send(Ok(UserAgentResponse {
+                            id: Some(request_id),
+                            payload: Some(response),
+                        })).await.is_err() {
+                            return;
+                        }
+                    }
+                    Ok(None) => {}
+                    Err(status) => {
+                        error!(?status, "Failed to process user agent request");
+                        let _ = bi.send(Err(status)).await;
+                        return;
+                    }
+                }
+            }
+        }
+    }
+}
+
+async fn dispatch_inner(
+    actor: &ActorRef<UserAgentSession>,
+    payload: UserAgentRequestPayload,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    match payload {
+        UserAgentRequestPayload::Vault(req) => vault::dispatch(actor, req).await,
+        UserAgentRequestPayload::Evm(req) => evm::dispatch(actor, req).await,
+        UserAgentRequestPayload::SdkClient(req) => sdk_client::dispatch(actor, req).await,
+        UserAgentRequestPayload::Auth(..) => {
+            warn!("Unsupported post-auth user agent auth request");
+            Err(Status::invalid_argument("Unsupported user-agent request"))
+        }
+    }
+}
+
+pub async fn start(
+    mut conn: UserAgentConnection,
+    mut bi: GrpcBi<UserAgentRequest, UserAgentResponse>,
+) {
+    let mut request_tracker = RequestTracker::default();
+
+    let pubkey = match auth::start(&mut conn, &mut bi, &mut request_tracker).await {
+        Ok(pubkey) => pubkey,
+        Err(e) => {
+            warn!(error = ?e, "Authentication failed");
+            return;
+        }
+    };
+
+    let (oob_sender, oob_receiver) = mpsc::channel(16);
+    let oob_adapter = OutOfBandAdapter(oob_sender);
+
+    let actor = UserAgentSession::spawn(UserAgentSession::new(conn, Box::new(oob_adapter)));
+    let actor_for_cleanup = actor.clone();
+
+    info!(?pubkey, "User authenticated successfully");
+    dispatch_loop(bi, actor, oob_receiver, request_tracker).await;
+    actor_for_cleanup.kill();
+}

server/crates/arbiter-server/src/grpc/user_agent/auth.rs

@@ -0,0 +1,194 @@
+use arbiter_proto::{
+    proto::user_agent::{
+        UserAgentRequest, UserAgentResponse,
+        auth::{
+            self as proto_auth, AuthChallenge as ProtoAuthChallenge,
+            AuthChallengeRequest as ProtoAuthChallengeRequest,
+            AuthChallengeSolution as ProtoAuthChallengeSolution, AuthResult as ProtoAuthResult,
+            KeyType as ProtoKeyType, request::Payload as AuthRequestPayload,
+            response::Payload as AuthResponsePayload,
+        },
+        user_agent_request::Payload as UserAgentRequestPayload,
+        user_agent_response::Payload as UserAgentResponsePayload,
+    },
+    transport::{Bi, Error as TransportError, Receiver, Sender, grpc::GrpcBi},
+};
+use async_trait::async_trait;
+use tonic::Status;
+use tracing::warn;
+
+use crate::{
+    actors::user_agent::{AuthPublicKey, UserAgentConnection, auth},
+    db::models::KeyType,
+    grpc::request_tracker::RequestTracker,
+};
+
+pub struct AuthTransportAdapter<'a> {
+    bi: &'a mut GrpcBi<UserAgentRequest, UserAgentResponse>,
+    request_tracker: &'a mut RequestTracker,
+}
+
+impl<'a> AuthTransportAdapter<'a> {
+    pub fn new(
+        bi: &'a mut GrpcBi<UserAgentRequest, UserAgentResponse>,
+        request_tracker: &'a mut RequestTracker,
+    ) -> Self {
+        Self {
+            bi,
+            request_tracker,
+        }
+    }
+
+    async fn send_user_agent_response(
+        &mut self,
+        payload: AuthResponsePayload,
+    ) -> Result<(), TransportError> {
+        self.bi
+            .send(Ok(UserAgentResponse {
+                id: Some(self.request_tracker.current_request_id()),
+                payload: Some(UserAgentResponsePayload::Auth(proto_auth::Response {
+                    payload: Some(payload),
+                })),
+            }))
+            .await
+    }
+}
+
+#[async_trait]
+impl Sender<Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {
+    async fn send(
+        &mut self,
+        item: Result<auth::Outbound, auth::Error>,
+    ) -> Result<(), TransportError> {
+        use auth::{Error, Outbound};
+        let payload = match item {
+            Ok(Outbound::AuthChallenge { nonce }) => {
+                AuthResponsePayload::Challenge(ProtoAuthChallenge { nonce })
+            }
+            Ok(Outbound::AuthSuccess) => {
+                AuthResponsePayload::Result(ProtoAuthResult::Success.into())
+            }
+            Err(Error::UnregisteredPublicKey) => {
+                AuthResponsePayload::Result(ProtoAuthResult::InvalidKey.into())
+            }
+            Err(Error::InvalidChallengeSolution) => {
+                AuthResponsePayload::Result(ProtoAuthResult::InvalidSignature.into())
+            }
+            Err(Error::InvalidBootstrapToken) => {
+                AuthResponsePayload::Result(ProtoAuthResult::TokenInvalid.into())
+            }
+            Err(Error::Internal { details }) => {
+                return self.bi.send(Err(Status::internal(details))).await;
+            }
+            Err(Error::Transport) => {
+                return self
+                    .bi
+                    .send(Err(Status::unavailable("transport error")))
+                    .await;
+            }
+        };
+
+        self.send_user_agent_response(payload).await
+    }
+}
+
+#[async_trait]
+impl Receiver<auth::Inbound> for AuthTransportAdapter<'_> {
+    async fn recv(&mut self) -> Option<auth::Inbound> {
+        let request = match self.bi.recv().await? {
+            Ok(request) => request,
+            Err(error) => {
+                warn!(error = ?error, "Failed to receive user agent auth request");
+                return None;
+            }
+        };
+
+        match self.request_tracker.request(request.id) {
+            Ok(request_id) => request_id,
+            Err(error) => {
+                let _ = self.bi.send(Err(error)).await;
+                return None;
+            }
+        };
+
+        let Some(payload) = request.payload else {
+            warn!(
+                event = "received request with empty payload",
+                "grpc.useragent.auth_adapter"
+            );
+            return None;
+        };
+
+        let UserAgentRequestPayload::Auth(auth_request) = payload else {
+            let _ = self
+                .bi
+                .send(Err(Status::invalid_argument(
+                    "Unsupported user-agent auth request",
+                )))
+                .await;
+            return None;
+        };
+
+        let Some(payload) = auth_request.payload else {
+            warn!(
+                event = "received auth request with empty payload",
+                "grpc.useragent.auth_adapter"
+            );
+            return None;
+        };
+
+        match payload {
+            AuthRequestPayload::ChallengeRequest(ProtoAuthChallengeRequest {
+                pubkey,
+                bootstrap_token,
+                key_type,
+            }) => {
+                let Ok(key_type) = ProtoKeyType::try_from(key_type) else {
+                    warn!(
+                        event = "received request with invalid key type",
+                        "grpc.useragent.auth_adapter"
+                    );
+                    return None;
+                };
+                let key_type = match key_type {
+                    ProtoKeyType::Ed25519 => KeyType::Ed25519,
+                    ProtoKeyType::EcdsaSecp256k1 => KeyType::EcdsaSecp256k1,
+                    ProtoKeyType::Rsa => KeyType::Rsa,
+                    ProtoKeyType::Unspecified => {
+                        warn!(
+                            event = "received request with unspecified key type",
+                            "grpc.useragent.auth_adapter"
+                        );
+                        return None;
+                    }
+                };
+                let Ok(pubkey) = AuthPublicKey::try_from((key_type, pubkey)) else {
+                    warn!(
+                        event = "received request with invalid public key",
+                        "grpc.useragent.auth_adapter"
+                    );
+                    return None;
+                };
+
+                Some(auth::Inbound::AuthChallengeRequest {
+                    pubkey,
+                    bootstrap_token,
+                })
+            }
+            AuthRequestPayload::ChallengeSolution(ProtoAuthChallengeSolution { signature }) => {
+                Some(auth::Inbound::AuthChallengeSolution { signature })
+            }
+        }
+    }
+}
+
+impl Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {}
+
+pub async fn start(
+    conn: &mut UserAgentConnection,
+    bi: &mut GrpcBi<UserAgentRequest, UserAgentResponse>,
+    request_tracker: &mut RequestTracker,
+) -> Result<AuthPublicKey, auth::Error> {
+    let transport = AuthTransportAdapter::new(bi, request_tracker);
+    auth::authenticate(conn, transport).await
+}

server/crates/arbiter-server/src/grpc/user_agent/evm.rs

@@ -0,0 +1,234 @@
+use arbiter_proto::proto::{
+    evm::{
+        EvmError as ProtoEvmError, EvmGrantCreateRequest, EvmGrantCreateResponse,
+        EvmGrantDeleteRequest, EvmGrantDeleteResponse, EvmGrantList, EvmGrantListResponse,
+        EvmSignTransactionResponse, GrantEntry, WalletCreateResponse, WalletEntry, WalletList,
+        WalletListResponse, evm_grant_create_response::Result as EvmGrantCreateResult,
+        evm_grant_delete_response::Result as EvmGrantDeleteResult,
+        evm_grant_list_response::Result as EvmGrantListResult,
+        evm_sign_transaction_response::Result as EvmSignTransactionResult,
+        wallet_create_response::Result as WalletCreateResult,
+        wallet_list_response::Result as WalletListResult,
+    },
+    user_agent::{
+        evm::{
+            self as proto_evm, SignTransactionRequest as ProtoSignTransactionRequest,
+            request::Payload as EvmRequestPayload, response::Payload as EvmResponsePayload,
+        },
+        user_agent_response::Payload as UserAgentResponsePayload,
+    },
+};
+use kameo::actor::ActorRef;
+use tonic::Status;
+use tracing::warn;
+
+use crate::{
+    actors::user_agent::{
+        UserAgentSession,
+        session::connection::{
+            HandleEvmWalletCreate, HandleEvmWalletList, HandleGrantCreate, HandleGrantDelete,
+            HandleGrantList, HandleSignTransaction,
+            SignTransactionError as SessionSignTransactionError,
+        },
+    },
+    grpc::{
+        Convert, TryConvert,
+        common::inbound::{RawEvmAddress, RawEvmTransaction},
+    },
+};
+
+fn wrap_evm_response(payload: EvmResponsePayload) -> UserAgentResponsePayload {
+    UserAgentResponsePayload::Evm(proto_evm::Response {
+        payload: Some(payload),
+    })
+}
+
+pub(super) async fn dispatch(
+    actor: &ActorRef<UserAgentSession>,
+    req: proto_evm::Request,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    let Some(payload) = req.payload else {
+        return Err(Status::invalid_argument("Missing EVM request payload"));
+    };
+
+    match payload {
+        EvmRequestPayload::WalletCreate(_) => handle_wallet_create(actor).await,
+        EvmRequestPayload::WalletList(_) => handle_wallet_list(actor).await,
+        EvmRequestPayload::GrantCreate(req) => handle_grant_create(actor, req).await,
+        EvmRequestPayload::GrantDelete(req) => handle_grant_delete(actor, req).await,
+        EvmRequestPayload::GrantList(_) => handle_grant_list(actor).await,
+        EvmRequestPayload::SignTransaction(req) => handle_sign_transaction(actor, req).await,
+    }
+}
+
+async fn handle_wallet_create(
+    actor: &ActorRef<UserAgentSession>,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    let result = match actor.ask(HandleEvmWalletCreate {}).await {
+        Ok((wallet_id, address)) => WalletCreateResult::Wallet(WalletEntry {
+            id: wallet_id,
+            address: address.to_vec(),
+        }),
+        Err(err) => {
+            warn!(error = ?err, "Failed to create EVM wallet");
+            WalletCreateResult::Error(ProtoEvmError::Internal.into())
+        }
+    };
+    Ok(Some(wrap_evm_response(EvmResponsePayload::WalletCreate(
+        WalletCreateResponse {
+            result: Some(result),
+        },
+    ))))
+}
+
+async fn handle_wallet_list(
+    actor: &ActorRef<UserAgentSession>,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    let result = match actor.ask(HandleEvmWalletList {}).await {
+        Ok(wallets) => WalletListResult::Wallets(WalletList {
+            wallets: wallets
+                .into_iter()
+                .map(|(id, address)| WalletEntry {
+                    address: address.to_vec(),
+                    id,
+                })
+                .collect(),
+        }),
+        Err(err) => {
+            warn!(error = ?err, "Failed to list EVM wallets");
+            WalletListResult::Error(ProtoEvmError::Internal.into())
+        }
+    };
+    Ok(Some(wrap_evm_response(EvmResponsePayload::WalletList(
+        WalletListResponse {
+            result: Some(result),
+        },
+    ))))
+}
+
+async fn handle_grant_list(
+    actor: &ActorRef<UserAgentSession>,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    let result = match actor.ask(HandleGrantList {}).await {
+        Ok(grants) => EvmGrantListResult::Grants(EvmGrantList {
+            grants: grants
+                .into_iter()
+                .map(|grant| GrantEntry {
+                    id: grant.id,
+                    wallet_access_id: grant.shared.wallet_access_id,
+                    shared: Some(grant.shared.convert()),
+                    specific: Some(grant.settings.convert()),
+                })
+                .collect(),
+        }),
+        Err(err) => {
+            warn!(error = ?err, "Failed to list EVM grants");
+            EvmGrantListResult::Error(ProtoEvmError::Internal.into())
+        }
+    };
+    Ok(Some(wrap_evm_response(EvmResponsePayload::GrantList(
+        EvmGrantListResponse {
+            result: Some(result),
+        },
+    ))))
+}
+
+async fn handle_grant_create(
+    actor: &ActorRef<UserAgentSession>,
+    req: EvmGrantCreateRequest,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    let basic = req
+        .shared
+        .ok_or_else(|| Status::invalid_argument("Missing shared grant settings"))?
+        .try_convert()?;
+    let grant = req
+        .specific
+        .ok_or_else(|| Status::invalid_argument("Missing specific grant settings"))?
+        .try_convert()?;
+
+    let result = match actor.ask(HandleGrantCreate { basic, grant }).await {
+        Ok(grant_id) => EvmGrantCreateResult::GrantId(grant_id),
+        Err(err) => {
+            warn!(error = ?err, "Failed to create EVM grant");
+            EvmGrantCreateResult::Error(ProtoEvmError::Internal.into())
+        }
+    };
+    Ok(Some(wrap_evm_response(EvmResponsePayload::GrantCreate(
+        EvmGrantCreateResponse {
+            result: Some(result),
+        },
+    ))))
+}
+
+async fn handle_grant_delete(
+    actor: &ActorRef<UserAgentSession>,
+    req: EvmGrantDeleteRequest,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    let result = match actor
+        .ask(HandleGrantDelete {
+            grant_id: req.grant_id,
+        })
+        .await
+    {
+        Ok(()) => EvmGrantDeleteResult::Ok(()),
+        Err(err) => {
+            warn!(error = ?err, "Failed to delete EVM grant");
+            EvmGrantDeleteResult::Error(ProtoEvmError::Internal.into())
+        }
+    };
+    Ok(Some(wrap_evm_response(EvmResponsePayload::GrantDelete(
+        EvmGrantDeleteResponse {
+            result: Some(result),
+        },
+    ))))
+}
+
+async fn handle_sign_transaction(
+    actor: &ActorRef<UserAgentSession>,
+    req: ProtoSignTransactionRequest,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    let request = req
+        .request
+        .ok_or_else(|| Status::invalid_argument("Missing sign transaction request"))?;
+    let wallet_address = RawEvmAddress(request.wallet_address).try_convert()?;
+    let transaction = RawEvmTransaction(request.rlp_transaction).try_convert()?;
+
+    let response = match actor
+        .ask(HandleSignTransaction {
+            client_id: req.client_id,
+            wallet_address,
+            transaction,
+        })
+        .await
+    {
+        Ok(signature) => EvmSignTransactionResponse {
+            result: Some(EvmSignTransactionResult::Signature(
+                signature.as_bytes().to_vec(),
+            )),
+        },
+        Err(kameo::error::SendError::HandlerError(SessionSignTransactionError::Vet(vet_error))) => {
+            EvmSignTransactionResponse {
+                result: Some(vet_error.convert()),
+            }
+        }
+        Err(kameo::error::SendError::HandlerError(SessionSignTransactionError::Internal)) => {
+            EvmSignTransactionResponse {
+                result: Some(EvmSignTransactionResult::Error(
+                    ProtoEvmError::Internal.into(),
+                )),
+            }
+        }
+        Err(err) => {
+            warn!(error = ?err, "Failed to sign EVM transaction");
+            EvmSignTransactionResponse {
+                result: Some(EvmSignTransactionResult::Error(
+                    ProtoEvmError::Internal.into(),
+                )),
+            }
+        }
+    };
+
+    Ok(Some(wrap_evm_response(
+        EvmResponsePayload::SignTransaction(response),
+    )))
+}

server/crates/arbiter-server/src/grpc/user_agent/inbound.rs

@@ -0,0 +1,170 @@
+use alloy::primitives::{Address, U256};
+use arbiter_proto::proto::evm::{
+    EtherTransferSettings as ProtoEtherTransferSettings, SharedSettings as ProtoSharedSettings,
+    SpecificGrant as ProtoSpecificGrant, TokenTransferSettings as ProtoTokenTransferSettings,
+    TransactionRateLimit as ProtoTransactionRateLimit, VolumeRateLimit as ProtoVolumeRateLimit,
+    specific_grant::Grant as ProtoSpecificGrantType,
+};
+use arbiter_proto::proto::user_agent::sdk_client::{
+    WalletAccess, WalletAccessEntry as SdkClientWalletAccess,
+};
+use chrono::{DateTime, TimeZone, Utc};
+use prost_types::Timestamp as ProtoTimestamp;
+use tonic::Status;
+
+use crate::db::models::{CoreEvmWalletAccess, NewEvmWalletAccess};
+use crate::grpc::Convert;
+use crate::{
+    evm::policies::{
+        SharedGrantSettings, SpecificGrant, TransactionRateLimit, VolumeRateLimit, ether_transfer,
+        token_transfers,
+    },
+    grpc::TryConvert,
+};
+
+fn address_from_bytes(bytes: Vec<u8>) -> Result<Address, Status> {
+    if bytes.len() != 20 {
+        return Err(Status::invalid_argument("Invalid EVM address"));
+    }
+    Ok(Address::from_slice(&bytes))
+}
+
+fn u256_from_proto_bytes(bytes: &[u8]) -> Result<U256, Status> {
+    if bytes.len() > 32 {
+        return Err(Status::invalid_argument("Invalid U256 byte length"));
+    }
+    Ok(U256::from_be_slice(bytes))
+}
+
+impl TryConvert for ProtoTimestamp {
+    type Output = DateTime<Utc>;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<DateTime<Utc>, Status> {
+        Utc.timestamp_opt(self.seconds, self.nanos as u32)
+            .single()
+            .ok_or_else(|| Status::invalid_argument("Invalid timestamp"))
+    }
+}
+
+impl TryConvert for ProtoTransactionRateLimit {
+    type Output = TransactionRateLimit;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<TransactionRateLimit, Status> {
+        Ok(TransactionRateLimit {
+            count: self.count,
+            window: chrono::Duration::seconds(self.window_secs),
+        })
+    }
+}
+
+impl TryConvert for ProtoVolumeRateLimit {
+    type Output = VolumeRateLimit;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<VolumeRateLimit, Status> {
+        Ok(VolumeRateLimit {
+            max_volume: u256_from_proto_bytes(&self.max_volume)?,
+            window: chrono::Duration::seconds(self.window_secs),
+        })
+    }
+}
+
+impl TryConvert for ProtoSharedSettings {
+    type Output = SharedGrantSettings;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<SharedGrantSettings, Status> {
+        Ok(SharedGrantSettings {
+            wallet_access_id: self.wallet_access_id,
+            chain: self.chain_id,
+            valid_from: self
+                .valid_from
+                .map(ProtoTimestamp::try_convert)
+                .transpose()?,
+            valid_until: self
+                .valid_until
+                .map(ProtoTimestamp::try_convert)
+                .transpose()?,
+            max_gas_fee_per_gas: self
+                .max_gas_fee_per_gas
+                .as_deref()
+                .map(u256_from_proto_bytes)
+                .transpose()?,
+            max_priority_fee_per_gas: self
+                .max_priority_fee_per_gas
+                .as_deref()
+                .map(u256_from_proto_bytes)
+                .transpose()?,
+            rate_limit: self
+                .rate_limit
+                .map(ProtoTransactionRateLimit::try_convert)
+                .transpose()?,
+        })
+    }
+}
+
+impl TryConvert for ProtoSpecificGrant {
+    type Output = SpecificGrant;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<SpecificGrant, Status> {
+        match self.grant {
+            Some(ProtoSpecificGrantType::EtherTransfer(ProtoEtherTransferSettings {
+                targets,
+                limit,
+            })) => Ok(SpecificGrant::EtherTransfer(ether_transfer::Settings {
+                target: targets
+                    .into_iter()
+                    .map(address_from_bytes)
+                    .collect::<Result<_, _>>()?,
+                limit: limit
+                    .ok_or_else(|| {
+                        Status::invalid_argument("Missing ether transfer volume rate limit")
+                    })?
+                    .try_convert()?,
+            })),
+            Some(ProtoSpecificGrantType::TokenTransfer(ProtoTokenTransferSettings {
+                token_contract,
+                target,
+                volume_limits,
+            })) => Ok(SpecificGrant::TokenTransfer(token_transfers::Settings {
+                token_contract: address_from_bytes(token_contract)?,
+                target: target.map(address_from_bytes).transpose()?,
+                volume_limits: volume_limits
+                    .into_iter()
+                    .map(ProtoVolumeRateLimit::try_convert)
+                    .collect::<Result<_, _>>()?,
+            })),
+            None => Err(Status::invalid_argument("Missing specific grant kind")),
+        }
+    }
+}
+
+impl Convert for WalletAccess {
+    type Output = NewEvmWalletAccess;
+
+    fn convert(self) -> Self::Output {
+        NewEvmWalletAccess {
+            wallet_id: self.wallet_id,
+            client_id: self.sdk_client_id,
+        }
+    }
+}
+
+impl TryConvert for SdkClientWalletAccess {
+    type Output = CoreEvmWalletAccess;
+    type Error = Status;
+
+    fn try_convert(self) -> Result<CoreEvmWalletAccess, Status> {
+        let Some(access) = self.access else {
+            return Err(Status::invalid_argument("Missing wallet access entry"));
+        };
+        Ok(CoreEvmWalletAccess {
+            wallet_id: access.wallet_id,
+            client_id: access.sdk_client_id,
+            id: self.id,
+        })
+    }
+}

server/crates/arbiter-server/src/grpc/user_agent/outbound.rs

@@ -0,0 +1,111 @@
+use arbiter_proto::proto::{
+    evm::{
+        EtherTransferSettings as ProtoEtherTransferSettings, SharedSettings as ProtoSharedSettings,
+        SpecificGrant as ProtoSpecificGrant, TokenTransferSettings as ProtoTokenTransferSettings,
+        TransactionRateLimit as ProtoTransactionRateLimit, VolumeRateLimit as ProtoVolumeRateLimit,
+        specific_grant::Grant as ProtoSpecificGrantType,
+    },
+    user_agent::sdk_client::{WalletAccess, WalletAccessEntry as ProtoSdkClientWalletAccess},
+};
+use chrono::{DateTime, Utc};
+use prost_types::Timestamp as ProtoTimestamp;
+
+use crate::{
+    db::models::EvmWalletAccess,
+    evm::policies::{SharedGrantSettings, SpecificGrant, TransactionRateLimit, VolumeRateLimit},
+    grpc::Convert,
+};
+
+impl Convert for DateTime<Utc> {
+    type Output = ProtoTimestamp;
+
+    fn convert(self) -> ProtoTimestamp {
+        ProtoTimestamp {
+            seconds: self.timestamp(),
+            nanos: self.timestamp_subsec_nanos() as i32,
+        }
+    }
+}
+
+impl Convert for TransactionRateLimit {
+    type Output = ProtoTransactionRateLimit;
+
+    fn convert(self) -> ProtoTransactionRateLimit {
+        ProtoTransactionRateLimit {
+            count: self.count,
+            window_secs: self.window.num_seconds(),
+        }
+    }
+}
+
+impl Convert for VolumeRateLimit {
+    type Output = ProtoVolumeRateLimit;
+
+    fn convert(self) -> ProtoVolumeRateLimit {
+        ProtoVolumeRateLimit {
+            max_volume: self.max_volume.to_be_bytes::<32>().to_vec(),
+            window_secs: self.window.num_seconds(),
+        }
+    }
+}
+
+impl Convert for SharedGrantSettings {
+    type Output = ProtoSharedSettings;
+
+    fn convert(self) -> ProtoSharedSettings {
+        ProtoSharedSettings {
+            wallet_access_id: self.wallet_access_id,
+            chain_id: self.chain,
+            valid_from: self.valid_from.map(DateTime::convert),
+            valid_until: self.valid_until.map(DateTime::convert),
+            max_gas_fee_per_gas: self
+                .max_gas_fee_per_gas
+                .map(|value| value.to_be_bytes::<32>().to_vec()),
+            max_priority_fee_per_gas: self
+                .max_priority_fee_per_gas
+                .map(|value| value.to_be_bytes::<32>().to_vec()),
+            rate_limit: self.rate_limit.map(TransactionRateLimit::convert),
+        }
+    }
+}
+
+impl Convert for SpecificGrant {
+    type Output = ProtoSpecificGrant;
+
+    fn convert(self) -> ProtoSpecificGrant {
+        let grant = match self {
+            SpecificGrant::EtherTransfer(s) => {
+                ProtoSpecificGrantType::EtherTransfer(ProtoEtherTransferSettings {
+                    targets: s.target.into_iter().map(|a| a.to_vec()).collect(),
+                    limit: Some(s.limit.convert()),
+                })
+            }
+            SpecificGrant::TokenTransfer(s) => {
+                ProtoSpecificGrantType::TokenTransfer(ProtoTokenTransferSettings {
+                    token_contract: s.token_contract.to_vec(),
+                    target: s.target.map(|a| a.to_vec()),
+                    volume_limits: s
+                        .volume_limits
+                        .into_iter()
+                        .map(VolumeRateLimit::convert)
+                        .collect(),
+                })
+            }
+        };
+        ProtoSpecificGrant { grant: Some(grant) }
+    }
+}
+
+impl Convert for EvmWalletAccess {
+    type Output = ProtoSdkClientWalletAccess;
+
+    fn convert(self) -> Self::Output {
+        Self::Output {
+            id: self.id,
+            access: Some(WalletAccess {
+                wallet_id: self.wallet_id,
+                sdk_client_id: self.client_id,
+            }),
+        }
+    }
+}

server/crates/arbiter-server/src/grpc/user_agent/sdk_client.rs

@@ -0,0 +1,194 @@
+use arbiter_proto::proto::{
+    shared::ClientInfo as ProtoClientMetadata,
+    user_agent::{
+        sdk_client::{
+            self as proto_sdk_client, ConnectionCancel as ProtoSdkClientConnectionCancel,
+            ConnectionRequest as ProtoSdkClientConnectionRequest,
+            ConnectionResponse as ProtoSdkClientConnectionResponse, Entry as ProtoSdkClientEntry,
+            Error as ProtoSdkClientError, GrantWalletAccess as ProtoSdkClientGrantWalletAccess,
+            List as ProtoSdkClientList, ListResponse as ProtoSdkClientListResponse,
+            ListWalletAccessResponse, RevokeWalletAccess as ProtoSdkClientRevokeWalletAccess,
+            list_response::Result as ProtoSdkClientListResult,
+            request::Payload as SdkClientRequestPayload,
+            response::Payload as SdkClientResponsePayload,
+        },
+        user_agent_response::Payload as UserAgentResponsePayload,
+    },
+};
+use kameo::actor::ActorRef;
+use tonic::Status;
+use tracing::{info, warn};
+
+use crate::{
+    actors::user_agent::{
+        OutOfBand, UserAgentSession,
+        session::connection::{
+            HandleGrantEvmWalletAccess, HandleListWalletAccess, HandleNewClientApprove,
+            HandleRevokeEvmWalletAccess, HandleSdkClientList,
+        },
+    },
+    db::models::NewEvmWalletAccess,
+    grpc::Convert,
+};
+
+fn wrap_sdk_client_response(payload: SdkClientResponsePayload) -> UserAgentResponsePayload {
+    UserAgentResponsePayload::SdkClient(proto_sdk_client::Response {
+        payload: Some(payload),
+    })
+}
+
+pub(super) fn out_of_band_payload(oob: OutOfBand) -> UserAgentResponsePayload {
+    match oob {
+        OutOfBand::ClientConnectionRequest { profile } => wrap_sdk_client_response(
+            SdkClientResponsePayload::ConnectionRequest(ProtoSdkClientConnectionRequest {
+                pubkey: profile.pubkey.to_bytes().to_vec(),
+                info: Some(ProtoClientMetadata {
+                    name: profile.metadata.name,
+                    description: profile.metadata.description,
+                    version: profile.metadata.version,
+                }),
+            }),
+        ),
+        OutOfBand::ClientConnectionCancel { pubkey } => wrap_sdk_client_response(
+            SdkClientResponsePayload::ConnectionCancel(ProtoSdkClientConnectionCancel {
+                pubkey: pubkey.to_bytes().to_vec(),
+            }),
+        ),
+    }
+}
+
+pub(super) async fn dispatch(
+    actor: &ActorRef<UserAgentSession>,
+    req: proto_sdk_client::Request,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    let Some(payload) = req.payload else {
+        return Err(Status::invalid_argument(
+            "Missing SDK client request payload",
+        ));
+    };
+
+    match payload {
+        SdkClientRequestPayload::ConnectionResponse(resp) => {
+            handle_connection_response(actor, resp).await
+        }
+        SdkClientRequestPayload::Revoke(_) => Err(Status::unimplemented(
+            "SdkClientRevoke is not yet implemented",
+        )),
+        SdkClientRequestPayload::List(_) => handle_list(actor).await,
+        SdkClientRequestPayload::GrantWalletAccess(req) => {
+            handle_grant_wallet_access(actor, req).await
+        }
+        SdkClientRequestPayload::RevokeWalletAccess(req) => {
+            handle_revoke_wallet_access(actor, req).await
+        }
+        SdkClientRequestPayload::ListWalletAccess(_) => handle_list_wallet_access(actor).await,
+    }
+}
+
+async fn handle_connection_response(
+    actor: &ActorRef<UserAgentSession>,
+    resp: ProtoSdkClientConnectionResponse,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    let pubkey_bytes = <[u8; 32]>::try_from(resp.pubkey)
+        .map_err(|_| Status::invalid_argument("Invalid Ed25519 public key length"))?;
+    let pubkey = ed25519_dalek::VerifyingKey::from_bytes(&pubkey_bytes)
+        .map_err(|_| Status::invalid_argument("Invalid Ed25519 public key"))?;
+
+    actor
+        .ask(HandleNewClientApprove {
+            approved: resp.approved,
+            pubkey,
+        })
+        .await
+        .map_err(|err| {
+            warn!(?err, "Failed to process client connection response");
+            Status::internal("Failed to process response")
+        })?;
+
+    Ok(None)
+}
+
+async fn handle_list(
+    actor: &ActorRef<UserAgentSession>,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    let result = match actor.ask(HandleSdkClientList {}).await {
+        Ok(clients) => ProtoSdkClientListResult::Clients(ProtoSdkClientList {
+            clients: clients
+                .into_iter()
+                .map(|(client, metadata)| ProtoSdkClientEntry {
+                    id: client.id,
+                    pubkey: client.public_key,
+                    info: Some(ProtoClientMetadata {
+                        name: metadata.name,
+                        description: metadata.description,
+                        version: metadata.version,
+                    }),
+                    created_at: client.created_at.0.timestamp() as i32,
+                })
+                .collect(),
+        }),
+        Err(err) => {
+            warn!(error = ?err, "Failed to list SDK clients");
+            ProtoSdkClientListResult::Error(ProtoSdkClientError::Internal.into())
+        }
+    };
+    Ok(Some(wrap_sdk_client_response(
+        SdkClientResponsePayload::List(ProtoSdkClientListResponse {
+            result: Some(result),
+        }),
+    )))
+}
+
+async fn handle_grant_wallet_access(
+    actor: &ActorRef<UserAgentSession>,
+    req: ProtoSdkClientGrantWalletAccess,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    let entries: Vec<NewEvmWalletAccess> = req.accesses.into_iter().map(|a| a.convert()).collect();
+    match actor.ask(HandleGrantEvmWalletAccess { entries }).await {
+        Ok(()) => {
+            info!("Successfully granted wallet access");
+            Ok(None)
+        }
+        Err(err) => {
+            warn!(error = ?err, "Failed to grant wallet access");
+            Err(Status::internal("Failed to grant wallet access"))
+        }
+    }
+}
+
+async fn handle_revoke_wallet_access(
+    actor: &ActorRef<UserAgentSession>,
+    req: ProtoSdkClientRevokeWalletAccess,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    match actor
+        .ask(HandleRevokeEvmWalletAccess {
+            entries: req.accesses,
+        })
+        .await
+    {
+        Ok(()) => {
+            info!("Successfully revoked wallet access");
+            Ok(None)
+        }
+        Err(err) => {
+            warn!(error = ?err, "Failed to revoke wallet access");
+            Err(Status::internal("Failed to revoke wallet access"))
+        }
+    }
+}
+
+async fn handle_list_wallet_access(
+    actor: &ActorRef<UserAgentSession>,
+) -> Result<Option<UserAgentResponsePayload>, Status> {
+    match actor.ask(HandleListWalletAccess {}).await {
+        Ok(accesses) => Ok(Some(wrap_sdk_client_response(
+            SdkClientResponsePayload::ListWalletAccess(ListWalletAccessResponse {
+                accesses: accesses.into_iter().map(|a| a.convert()).collect(),
+            }),
+        ))),
+        Err(err) => {
+            warn!(error = ?err, "Failed to list wallet access");
+            Err(Status::internal("Failed to list wallet access"))
+        }
+    }
+}