refactor(arbiter-client): rewrite errors to terrros

Reviewed-on: #34

.gitignore

@@ -2,3 +2,4 @@ target/
 scripts/__pycache__/
 .DS_Store
 .cargo/config.toml
+.vscode/

.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/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.
+- **`MessageRouter`** — Coordinates streaming messages 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.
+- **`MessageRouter`** — Coordinates streaming messages 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.
@@ -68,9 +82,21 @@ 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

mise.lock

@@ -1,7 +1,37 @@
+# @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-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.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-edit"]]
+version = "0.13.9"
+backend = "cargo:cargo-edit"
+
 [[tools."cargo:cargo-features"]]
 version = "1.0.0"
 backend = "cargo:cargo-features"
@@ -42,6 +72,10 @@ backend = "cargo:diesel_cli"
 default-features = "false"
 features = "sqlite,sqlite-bundled"
 
+[[tools."cargo:rinf_cli"]]
+version = "8.9.1"
+backend = "cargo:rinf_cli"
+
 [[tools.flutter]]
 version = "3.38.9-stable"
 backend = "asdf:flutter"
@@ -49,20 +83,50 @@ 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"}
-"platforms.macos-arm64" = { checksum = "sha256:b9576b5fa1a1ef3fe13a8c91d9d8204b46545759bea5ae155cd6ba2ea4cdaeed", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-osx-aarch_64.zip"}
-"platforms.macos-x64" = { checksum = "sha256:312f04713946921cc0187ef34df80241ddca1bab6f564c636885fd2cc90d3f88", url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.6/protoc-29.6-osx-x86_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"]
+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.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"}
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+
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+
+[tools.python."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.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"
+
+[tools.python."platforms.macos-x64"]
+checksum = "sha256:76f1cc26e3d262eae8ca546a93e8bded10cf0323613f7e246fea2e10a8115eb7"
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+
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+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.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']
+outputs = ['useragent/lib/proto/*']
+run = '''
+dart pub global activate protoc_plugin && \
+protoc --dart_out=grpc:useragent/lib/proto --proto_path=protobufs/ protobufs/*.proto
+'''

protobufs/client.proto

@@ -3,6 +3,7 @@ syntax = "proto3";
 package arbiter.client;
 
 import "evm.proto";
+import "google/protobuf/empty.proto";
 
 message AuthChallengeRequest {
   bytes pubkey = 1;
@@ -17,31 +18,40 @@ message AuthChallengeSolution {
   bytes signature = 1;
 }
 
-message AuthOk {}
+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;
+}
+
+enum VaultState {
+  VAULT_STATE_UNSPECIFIED = 0;
+  VAULT_STATE_UNBOOTSTRAPPED = 1;
+  VAULT_STATE_SEALED = 2;
+  VAULT_STATE_UNSEALED = 3;
+  VAULT_STATE_ERROR = 4;
+}
 
 message ClientRequest {
+  int32 request_id = 4;
   oneof payload {
     AuthChallengeRequest auth_challenge_request = 1;
     AuthChallengeSolution auth_challenge_solution = 2;
-    arbiter.evm.EvmSignTransactionRequest evm_sign_transaction = 3;
+    google.protobuf.Empty query_vault_state = 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;
-    AuthOk auth_ok = 2;
-    ClientConnectError client_connect_error = 5;
+    AuthResult auth_result = 2;
     arbiter.evm.EvmSignTransactionResponse evm_sign_transaction = 3;
     arbiter.evm.EvmAnalyzeTransactionResponse evm_analyze_transaction = 4;
+    VaultState vault_state = 6;
   }
 }

protobufs/user_agent.proto

@@ -2,8 +2,8 @@ syntax = "proto3";
 
 package arbiter.user_agent;
 
-import "google/protobuf/empty.proto";
 import "evm.proto";
+import "google/protobuf/empty.proto";
 
 enum KeyType {
   KEY_TYPE_UNSPECIFIED = 0;
@@ -68,15 +68,23 @@ message AuthChallengeRequest {
 }
 
 message AuthChallenge {
-  bytes pubkey = 1;
   int32 nonce = 2;
+  reserved 1;
 }
 
 message AuthChallengeSolution {
   bytes signature = 1;
 }
 
-message AuthOk {}
+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 UnsealStart {
   bytes client_pubkey = 1;
@@ -91,6 +99,12 @@ message UnsealEncryptedKey {
   bytes associated_data = 3;
 }
 
+message BootstrapEncryptedKey {
+  bytes nonce = 1;
+  bytes ciphertext = 2;
+  bytes associated_data = 3;
+}
+
 enum UnsealResult {
   UNSEAL_RESULT_UNSPECIFIED = 0;
   UNSEAL_RESULT_SUCCESS = 1;
@@ -98,6 +112,13 @@ enum UnsealResult {
   UNSEAL_RESULT_UNBOOTSTRAPPED = 3;
 }
 
+enum BootstrapResult {
+  BOOTSTRAP_RESULT_UNSPECIFIED = 0;
+  BOOTSTRAP_RESULT_SUCCESS = 1;
+  BOOTSTRAP_RESULT_ALREADY_BOOTSTRAPPED = 2;
+  BOOTSTRAP_RESULT_INVALID_KEY = 3;
+}
+
 enum VaultState {
   VAULT_STATE_UNSPECIFIED = 0;
   VAULT_STATE_UNBOOTSTRAPPED = 1;
@@ -106,7 +127,18 @@ enum VaultState {
   VAULT_STATE_ERROR = 4;
 }
 
+message SdkClientConnectionRequest {
+  bytes pubkey = 1;
+}
+
+message SdkClientConnectionResponse {
+  bool approved = 1;
+}
+
+message SdkClientConnectionCancel {}
+
 message UserAgentRequest {
+  int32 id = 16;
   oneof payload {
     AuthChallengeRequest auth_challenge_request = 1;
     AuthChallengeSolution auth_challenge_solution = 2;
@@ -118,16 +150,18 @@ message UserAgentRequest {
     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)
+    SdkClientConnectionResponse sdk_client_connection_response = 11;
     SdkClientApproveRequest sdk_client_approve = 12;
     SdkClientRevokeRequest sdk_client_revoke = 13;
     google.protobuf.Empty sdk_client_list = 14;
+    BootstrapEncryptedKey bootstrap_encrypted_key = 15;
   }
 }
 message UserAgentResponse {
+  optional int32 id = 16;
   oneof payload {
     AuthChallenge auth_challenge = 1;
-    AuthOk auth_ok = 2;
+    AuthResult auth_result = 2;
     UnsealStartResponse unseal_start_response = 3;
     UnsealResult unseal_result = 4;
     VaultState vault_state = 5;
@@ -136,9 +170,10 @@ message UserAgentResponse {
     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;
+    SdkClientConnectionResponse sdk_client_connection_response = 11;
+    SdkClientApproveResponse sdk_client_approve_response = 12;
+    SdkClientRevokeResponse sdk_client_revoke_response = 13;
+    SdkClientListResponse sdk_client_list_response = 14;
+    BootstrapResult bootstrap_result = 15;
   }
 }

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 +684,10 @@ dependencies = [
  "async-trait",
  "ed25519-dalek",
  "http",
+ "rand 0.10.0",
  "rustls-webpki",
- "thiserror",
+ "terrors",
+ "thiserror 2.0.18",
  "tokio",
  "tokio-stream",
  "tonic",
@@ -708,8 +710,9 @@ dependencies = [
  "rcgen",
  "rstest",
  "rustls-pki-types",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
+ "tokio-stream",
  "tonic",
  "tonic-prost",
  "tonic-prost-build",
@@ -733,6 +736,7 @@ dependencies = [
  "diesel-async",
  "diesel_migrations",
  "ed25519-dalek",
+ "fatality",
  "futures",
  "insta",
  "k256",
@@ -740,6 +744,7 @@ dependencies = [
  "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]]
@@ -4865,9 +4911,8 @@ dependencies = [
 
 [[package]]
 name = "terrors"
-version = "0.3.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "987fd8c678ca950df2a18b2c6e9da6ca511d449278fab3565efe0d49c0c07a5d"
+version = "0.5.1"
+source = "git+https://github.com/CleverWild/terrors#a0867fd9ca3fbb44c32e92113a917f1577b5716a"
 
 [[package]]
 name = "test-log"
@@ -4900,13 +4945,33 @@ 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 +5046,9 @@ 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 +5133,7 @@ dependencies = [
  "serde_spanned",
  "toml_datetime 0.7.5+spec-1.1.0",
  "toml_parser",
- "winnow",
+ "winnow 0.7.15",
 ]
 
 [[package]]
@@ -5082,32 +5147,32 @@ 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 +5936,15 @@ 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 +6074,7 @@ dependencies = [
  "nom",
  "oid-registry",
  "rusticata-macros",
- "thiserror",
+ "thiserror 2.0.18",
  "time",
 ]
 
@@ -6038,18 +6112,18 @@ 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

@@ -1,7 +1,5 @@
 [workspace]
-members = [
-    "crates/*",
-]
+members = ["crates/*"]
 resolver = "3"
 
 [workspace.lints.clippy]
@@ -9,23 +7,23 @@ 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 +41,4 @@ k256 = { version = "0.13.4", features = ["ecdsa", "pkcs8"] }
 rsa = { version = "0.9", features = ["sha2"] }
 sha2 = "0.10"
 spki = "0.7"
+terrors = { version = "0.5", git = "https://github.com/CleverWild/terrors" }

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 +21,7 @@ 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
+terrors.workspace = true

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

@@ -0,0 +1,103 @@
+use arbiter_proto::{
+    format_challenge,
+    proto::client::{
+        AuthChallengeRequest, AuthChallengeSolution, AuthResult, ClientRequest,
+        client_request::Payload as ClientRequestPayload,
+        client_response::Payload as ClientResponsePayload,
+    },
+};
+use ed25519_dalek::Signer as _;
+use terrors::OneOf;
+
+use crate::{
+    errors::{
+        ConnectError, MissingAuthChallengeError, UnexpectedAuthResponseError, map_auth_code_error,
+    },
+    transport::{ClientTransport, next_request_id},
+};
+
+async fn send_auth_challenge_request(
+    transport: &mut ClientTransport,
+    key: &ed25519_dalek::SigningKey,
+) -> std::result::Result<(), ConnectError> {
+    transport
+        .send(ClientRequest {
+            request_id: next_request_id(),
+            payload: Some(ClientRequestPayload::AuthChallengeRequest(
+                AuthChallengeRequest {
+                    pubkey: key.verifying_key().to_bytes().to_vec(),
+                },
+            )),
+        })
+        .await
+        .map_err(|_| OneOf::new(UnexpectedAuthResponseError))
+}
+
+async fn receive_auth_challenge(
+    transport: &mut ClientTransport,
+) -> std::result::Result<arbiter_proto::proto::client::AuthChallenge, ConnectError> {
+    let response = transport
+        .recv()
+        .await
+        .map_err(|_| OneOf::new(MissingAuthChallengeError))?;
+
+    let payload = response
+        .payload
+        .ok_or_else(|| OneOf::new(MissingAuthChallengeError))?;
+    match payload {
+        ClientResponsePayload::AuthChallenge(challenge) => Ok(challenge),
+        ClientResponsePayload::AuthResult(result) => Err(map_auth_code_error(result)),
+        _ => Err(OneOf::new(UnexpectedAuthResponseError)),
+    }
+}
+
+async fn send_auth_challenge_solution(
+    transport: &mut ClientTransport,
+    key: &ed25519_dalek::SigningKey,
+    challenge: arbiter_proto::proto::client::AuthChallenge,
+) -> std::result::Result<(), ConnectError> {
+    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::AuthChallengeSolution(
+                AuthChallengeSolution { signature },
+            )),
+        })
+        .await
+        .map_err(|_| OneOf::new(UnexpectedAuthResponseError))
+}
+
+async fn receive_auth_confirmation(
+    transport: &mut ClientTransport,
+) -> std::result::Result<(), ConnectError> {
+    let response = transport
+        .recv()
+        .await
+        .map_err(|_| OneOf::new(UnexpectedAuthResponseError))?;
+
+    let payload = response
+        .payload
+        .ok_or_else(|| OneOf::new(UnexpectedAuthResponseError))?;
+    match payload {
+        ClientResponsePayload::AuthResult(result)
+            if AuthResult::try_from(result).ok() == Some(AuthResult::Success) =>
+        {
+            Ok(())
+        }
+        ClientResponsePayload::AuthResult(result) => Err(map_auth_code_error(result)),
+        _ => Err(OneOf::new(UnexpectedAuthResponseError)),
+    }
+}
+
+pub(crate) async fn authenticate(
+    transport: &mut ClientTransport,
+    key: &ed25519_dalek::SigningKey,
+) -> std::result::Result<(), ConnectError> {
+    send_auth_challenge_request(transport, 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/client.rs

@@ -0,0 +1,82 @@
+use arbiter_proto::{proto::arbiter_service_client::ArbiterServiceClient, url::ArbiterUrl};
+use std::sync::Arc;
+use terrors::{Broaden as _, OneOf};
+use tokio::sync::{Mutex, mpsc};
+use tokio_stream::wrappers::ReceiverStream;
+use tonic::transport::ClientTlsConfig;
+
+use crate::{
+    auth::authenticate,
+    errors::ConnectError,
+    storage::{FileSigningKeyStorage, SigningKeyStorage},
+    transport::{BUFFER_LENGTH, ClientTransport},
+};
+
+#[cfg(feature = "evm")]
+use crate::errors::{ClientConnectionClosedError, ClientError};
+
+#[cfg(feature = "evm")]
+use crate::wallets::evm::ArbiterEvmWallet;
+
+pub struct ArbiterClient {
+    #[allow(dead_code)]
+    transport: Arc<Mutex<ClientTransport>>,
+}
+
+impl ArbiterClient {
+    pub async fn connect(url: ArbiterUrl) -> Result<Self, ConnectError> {
+        let storage = FileSigningKeyStorage::from_default_location().broaden()?;
+        Self::connect_with_storage(url, &storage).await
+    }
+
+    pub async fn connect_with_storage<S: SigningKeyStorage>(
+        url: ArbiterUrl,
+        storage: &S,
+    ) -> Result<Self, ConnectError> {
+        let key = storage.load_or_create().broaden()?;
+        Self::connect_with_key(url, key).await
+    }
+
+    pub async fn connect_with_key(
+        url: ArbiterUrl,
+        key: ed25519_dalek::SigningKey,
+    ) -> Result<Self, ConnectError> {
+        let anchor = webpki::anchor_from_trusted_cert(&url.ca_cert)
+            .map_err(OneOf::new)?
+            .to_owned();
+        let tls = ClientTlsConfig::new().trust_anchor(anchor);
+
+        let channel = tonic::transport::Channel::from_shared(format!("{}:{}", url.host, url.port))
+            .map_err(OneOf::new)?
+            .tls_config(tls)
+            .map_err(OneOf::new)?
+            .connect()
+            .await
+            .map_err(OneOf::new)?;
+
+        let mut client = ArbiterServiceClient::new(channel);
+        let (tx, rx) = mpsc::channel(BUFFER_LENGTH);
+        let response_stream = client
+            .client(ReceiverStream::new(rx))
+            .await
+            .map_err(OneOf::new)?
+            .into_inner();
+
+        let mut transport = ClientTransport {
+            sender: tx,
+            receiver: response_stream,
+        };
+
+        authenticate(&mut transport, &key).await?;
+
+        Ok(Self {
+            transport: Arc::new(Mutex::new(transport)),
+        })
+    }
+
+    #[cfg(feature = "evm")]
+    pub async fn evm_wallets(&self) -> Result<Vec<ArbiterEvmWallet>, ClientError> {
+        let _ = &self.transport;
+        Err(OneOf::new(ClientConnectionClosedError))
+    }
+}

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

@@ -0,0 +1,127 @@
+use terrors::OneOf;
+use thiserror::Error;
+
+#[cfg(feature = "evm")]
+use alloy::{primitives::ChainId, signers::Error as AlloySignerError};
+
+pub type StorageError = OneOf<(std::io::Error, InvalidKeyLengthError)>;
+
+pub type ConnectError = OneOf<(
+    tonic::transport::Error,
+    http::uri::InvalidUri,
+    webpki::Error,
+    tonic::Status,
+    MissingAuthChallengeError,
+    ApprovalDeniedError,
+    NoUserAgentsOnlineError,
+    UnexpectedAuthResponseError,
+    std::io::Error,
+    InvalidKeyLengthError,
+)>;
+
+pub type ClientError = OneOf<(tonic::Status, ClientConnectionClosedError)>;
+
+pub(crate) type ClientTransportError =
+    OneOf<(TransportChannelClosedError, TransportConnectionClosedError)>;
+
+#[cfg(feature = "evm")]
+pub(crate) type EvmWalletError = OneOf<(
+    EvmChainIdMismatchError,
+    EvmHashSigningUnsupportedError,
+    EvmTransactionSigningUnsupportedError,
+)>;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
+#[error("Invalid signing key length in storage: expected {expected} bytes, got {actual} bytes")]
+pub struct InvalidKeyLengthError {
+    pub expected: usize,
+    pub actual: usize,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
+#[error("Auth challenge was not returned by server")]
+pub struct MissingAuthChallengeError;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
+#[error("Client approval denied by User Agent")]
+pub struct ApprovalDeniedError;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
+#[error("No User Agents online to approve client")]
+pub struct NoUserAgentsOnlineError;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
+#[error("Unexpected auth response payload")]
+pub struct UnexpectedAuthResponseError;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
+#[error("Connection closed by server")]
+pub struct ClientConnectionClosedError;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
+#[error("Transport channel closed")]
+pub struct TransportChannelClosedError;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
+#[error("Connection closed by server")]
+pub struct TransportConnectionClosedError;
+
+#[cfg(feature = "evm")]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
+#[error("Transaction chain id mismatch: signer {signer}, tx {tx}")]
+pub struct EvmChainIdMismatchError {
+    pub signer: ChainId,
+    pub tx: ChainId,
+}
+
+#[cfg(feature = "evm")]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
+#[error("hash-only signing is not supported for ArbiterEvmWallet; use transaction signing")]
+pub struct EvmHashSigningUnsupportedError;
+
+#[cfg(feature = "evm")]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
+#[error("transaction signing is not supported by current arbiter.client protocol")]
+pub struct EvmTransactionSigningUnsupportedError;
+
+pub(crate) fn map_auth_code_error(code: i32) -> ConnectError {
+    use arbiter_proto::proto::client::AuthResult;
+
+    match AuthResult::try_from(code).unwrap_or(AuthResult::Unspecified) {
+        AuthResult::ApprovalDenied => OneOf::new(ApprovalDeniedError),
+        AuthResult::NoUserAgentsOnline => OneOf::new(NoUserAgentsOnlineError),
+        AuthResult::Unspecified
+        | AuthResult::Success
+        | AuthResult::InvalidKey
+        | AuthResult::InvalidSignature
+        | AuthResult::Internal => OneOf::new(UnexpectedAuthResponseError),
+    }
+}
+
+#[cfg(feature = "evm")]
+impl From<EvmChainIdMismatchError> for AlloySignerError {
+    fn from(value: EvmChainIdMismatchError) -> Self {
+        AlloySignerError::TransactionChainIdMismatch {
+            signer: value.signer,
+            tx: value.tx,
+        }
+    }
+}
+
+#[cfg(feature = "evm")]
+impl From<EvmHashSigningUnsupportedError> for AlloySignerError {
+    fn from(_value: EvmHashSigningUnsupportedError) -> Self {
+        AlloySignerError::other(
+            "hash-only signing is not supported for ArbiterEvmWallet; use transaction signing",
+        )
+    }
+}
+
+#[cfg(feature = "evm")]
+impl From<EvmTransactionSigningUnsupportedError> for AlloySignerError {
+    fn from(_value: EvmTransactionSigningUnsupportedError) -> Self {
+        AlloySignerError::other(
+            "transaction signing is not supported by current arbiter.client protocol",
+        )
+    }
+}

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

@@ -1,272 +1,13 @@
-use alloy::{
-    consensus::SignableTransaction,
-    network::TxSigner,
-    primitives::{Address, B256, ChainId, Signature},
-    signers::{Error, Result, Signer},
-};
-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;
+mod auth;
+mod client;
+mod errors;
+mod storage;
+mod transport;
+pub mod wallets;
 
-#[derive(Debug, thiserror::Error)]
-pub enum ConnectError {
-    #[error("Could not establish connection")]
-    Connection(#[from] tonic::transport::Error),
+pub use client::ArbiterClient;
+pub use errors::{ClientError, ConnectError, StorageError};
+pub use storage::{FileSigningKeyStorage, SigningKeyStorage};
 
-    #[error("Invalid server URI")]
-    InvalidUri(#[from] http::uri::InvalidUri),
-
-    #[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
-    }
-}
+#[cfg(feature = "evm")]
+pub use wallets::evm::ArbiterEvmWallet;

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

@@ -0,0 +1,130 @@
+use arbiter_proto::home_path;
+use std::path::{Path, PathBuf};
+use terrors::OneOf;
+
+use crate::errors::{InvalidKeyLengthError, StorageError};
+
+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()
+                .map_err(OneOf::new)?
+                .join(Self::DEFAULT_FILE_NAME),
+        ))
+    }
+
+    fn read_key(path: &Path) -> std::result::Result<ed25519_dalek::SigningKey, StorageError> {
+        let bytes = std::fs::read(path).map_err(OneOf::new)?;
+        let raw: [u8; 32] = bytes.try_into().map_err(|v: Vec<u8>| {
+            OneOf::new(InvalidKeyLengthError {
+                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).map_err(OneOf::new)?;
+        }
+
+        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).map_err(OneOf::new)?;
+                Ok(key)
+            }
+            Err(err) if err.kind() == std::io::ErrorKind::AlreadyExists => {
+                Self::read_key(&self.path)
+            }
+            Err(err) => Err(OneOf::new(err)),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{FileSigningKeyStorage, SigningKeyStorage};
+    use crate::errors::InvalidKeyLengthError;
+
+    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.narrow::<InvalidKeyLengthError, _>() {
+            Ok(invalid_len) => {
+                assert_eq!(invalid_len.expected, 32);
+                assert_eq!(invalid_len.actual, 31);
+            }
+            Err(other) => panic!("unexpected io error: {other:?}"),
+        }
+
+        std::fs::remove_file(path).expect("temp key file should be removable");
+    }
+}

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

@@ -0,0 +1,42 @@
+use arbiter_proto::proto::client::{ClientRequest, ClientResponse};
+use std::sync::atomic::{AtomicI32, Ordering};
+use terrors::OneOf;
+use tokio::sync::mpsc;
+
+use crate::errors::{
+    ClientTransportError, TransportChannelClosedError, TransportConnectionClosedError,
+};
+
+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)
+}
+
+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<(), ClientTransportError> {
+        self.sender
+            .send(request)
+            .await
+            .map_err(|_| OneOf::new(TransportChannelClosedError))
+    }
+
+    pub(crate) async fn recv(
+        &mut self,
+    ) -> std::result::Result<ClientResponse, ClientTransportError> {
+        match self.receiver.message().await {
+            Ok(Some(resp)) => Ok(resp),
+            Ok(None) => Err(OneOf::new(TransportConnectionClosedError)),
+            Err(_) => Err(OneOf::new(TransportConnectionClosedError)),
+        }
+    }
+}

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

@@ -0,0 +1,97 @@
+use alloy::{
+    consensus::SignableTransaction,
+    network::TxSigner,
+    primitives::{Address, B256, ChainId, Signature},
+    signers::{Result, Signer},
+};
+use async_trait::async_trait;
+use std::sync::Arc;
+use terrors::OneOf;
+use tokio::sync::Mutex;
+
+use crate::{
+    errors::{
+        EvmChainIdMismatchError, EvmHashSigningUnsupportedError,
+        EvmTransactionSigningUnsupportedError, EvmWalletError,
+    },
+    transport::ClientTransport,
+};
+
+pub struct ArbiterEvmWallet {
+    transport: Arc<Mutex<ClientTransport>>,
+    address: Address,
+    chain_id: Option<ChainId>,
+}
+
+impl ArbiterEvmWallet {
+    #[allow(dead_code)]
+    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>,
+    ) -> std::result::Result<(), EvmWalletError> {
+        if let Some(chain_id) = self.chain_id
+            && !tx.set_chain_id_checked(chain_id)
+        {
+            return Err(OneOf::new(EvmChainIdMismatchError {
+                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(EvmWalletError::new(EvmHashSigningUnsupportedError).into())
+    }
+
+    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> {
+        let _transport = self.transport.lock().await;
+        self.validate_chain_id(tx)
+            .map_err(OneOf::into::<alloy::signers::Error>)?;
+
+        Err(EvmWalletError::new(EvmTransactionSigningUnsupportedError).into())
+    }
+}

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

@@ -1,27 +1,32 @@
+use std::path::PathBuf;
 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) };
+    let manifest_dir = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR")?);
+    let protobuf_dir = manifest_dir.join(PROTOBUF_DIR);
+    let protoc_include = protoc_bin_vendored::include_path()?;
+    let protoc_path = protoc_bin_vendored::protoc_bin_path()?;
+
+    unsafe {
+        std::env::set_var("PROTOC", &protoc_path);
+        std::env::set_var("PROTOC_INCLUDE", &protoc_include);
     }
 
-    println!("cargo::rerun-if-changed={PROTOBUF_DIR}");
+    println!("cargo::rerun-if-changed={}", protobuf_dir.display());
 
     configure()
         .message_attribute(".", "#[derive(::kameo::Reply)]")
+        .compile_well_known_types(true)
         .compile_protos(
             &[
-                format!("{}/arbiter.proto", PROTOBUF_DIR),
-                format!("{}/user_agent.proto", PROTOBUF_DIR),
-                format!("{}/client.proto", PROTOBUF_DIR),
-                format!("{}/evm.proto", PROTOBUF_DIR),
+                protobuf_dir.join("arbiter.proto"),
+                protobuf_dir.join("user_agent.proto"),
+                protobuf_dir.join("client.proto"),
+                protobuf_dir.join("evm.proto"),
             ],
-            &[PROTOBUF_DIR.to_string()],
-        )
-        .unwrap();
+            &[protobuf_dir],
+        )?;
     Ok(())
 }

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

@@ -3,6 +3,12 @@ pub mod url;
 
 use base64::{Engine, prelude::BASE64_STANDARD};
 
+pub mod google {
+    pub mod protobuf {
+        tonic::include_proto!("google.protobuf");
+    }
+}
+
 pub mod proto {
     tonic::include_proto!("arbiter");
 

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`])
-//! - transport adapters push concrete stream items to an underlying IO layer
-//! - transport boundaries translate between protocol-facing and transport-facing
-//!   item types via direction-specific converters
+//! The abstraction is split into:
+//! - [`Sender`] for outbound delivery
+//! - [`Receiver`] for inbound delivery
+//! - [`Bi`] as the combined duplex form (`Sender + Receiver`)
 //!
-//! [`Bi`] is intentionally minimal and transport-agnostic:
-//! - [`Bi::recv`] yields inbound protocol messages
-//! - [`Bi::send`] accepts outbound protocol/domain items
+//! This split lets code depend only on the half it actually needs. For
+//! example, some actor/session code only sends out-of-band messages, while
+//! 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
-//! parameterized by protocol message directions, the generic parameters are
-//! declared as `Inbound` first, then `Outbound`.
+//! This module consistently uses `Inbound` first and `Outbound` second in
+//! generic parameter lists.
 //!
-//! 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,
-//! inbound-related converter parameters are declared before outbound-related
-//! converter parameters.
+//! [`expect_message`] is a small helper for linear protocol steps: it reads one
+//! inbound message from a transport and extracts a typed value from it, failing
+//! if the channel closes or the message shape is not what the caller expected.
 //!
-//! [`RecvConverter`] and [`SendConverter`] are infallible conversion traits used
-//! by adapters to map between protocol-facing and transport-facing item types.
-//! 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
-//! ```
+//! [`DummyTransport`] is a no-op implementation useful for tests and local
+//! actor execution where no real stream exists.
 //!
 //! # Design Notes
 //!
-//! - `send()` returns [`Error`] only for transport delivery failures (for
-//!   example, when the outbound channel is closed).
-//! - [`grpc::GrpcAdapter`] logs tonic receive errors and treats them as stream
-//!   closure (`None`).
-//! - When protocol-facing and transport-facing types are identical, use
-//!   [`IdentityRecvConverter`] / [`IdentitySendConverter`].
+//! - [`Bi::send`] returns [`Error`] only for transport delivery failures, such
+//!   as a closed outbound channel.
+//! - [`Bi::recv`] returns `None` when the underlying transport closes.
+//! - Message translation is intentionally out of scope for this module.
 
 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.
-pub trait RecvConverter: Send + Sync + 'static {
-    type Input;
-    type Output;
+/// Minimal bidirectional transport abstraction used by protocol code.
+///
+/// `Bi<Inbound, Outbound>` is the combined duplex form of [`Sender`] and
+/// [`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.
-pub trait SendConverter: Send + Sync + 'static {
-    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,
-            }
-        }
-    }
+    fn split(self) -> (Self::Sender, Self::Receiver);
+    fn from_parts(sender: Self::Sender, receiver: Self::Receiver) -> Self;
 }
 
 /// 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> {
-    pub fn new() -> Self {
+impl<Inbound, Outbound> Default for DummyTransport<Inbound, Outbound> {
+    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-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-async = { version = "0.7.4", features = [
+diesel = { version = "2.3.7", features = ["chrono", "returning_clauses_for_sqlite_3_35", "serde_json", "time", "uuid"] }
+diesel-async = { version = "0.8.0", features = [
     "bb8",
     "migrations",
     "sqlite",
@@ -27,6 +27,7 @@ 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"
@@ -43,13 +44,14 @@ 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
 spki.workspace = true
 alloy.workspace = true
+prost-types.workspace = true
 arbiter-tokens-registry.path = "../arbiter-tokens-registry"
 
 [dev-dependencies]

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

@@ -157,3 +157,5 @@ create table if not exists evm_ether_transfer_grant_target (
 
 create unique index if not exists uniq_ether_transfer_target on evm_ether_transfer_grant_target(grant_id, address);
 
+CREATE UNIQUE INDEX program_client_public_key_unique
+    ON program_client (public_key);

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

@@ -3,12 +3,7 @@ use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
 use kameo::{Actor, messages};
 use miette::Diagnostic;
-use rand::{
-    RngExt,
-    distr::{Alphanumeric},
-    make_rng,
-    rngs::StdRng,
-};
+use rand::{RngExt, distr::Alphanumeric, make_rng, rngs::StdRng};
 use thiserror::Error;
 
 use crate::db::{self, DatabasePool, schema};
@@ -61,7 +56,6 @@ 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 +1,62 @@
 use arbiter_proto::{
     format_challenge,
-    proto::client::{
-        AuthChallenge, AuthChallengeSolution, ClientConnectError, ClientRequest, ClientResponse,
-        client_connect_error::Code as ConnectErrorCode,
-        client_request::Payload as ClientRequestPayload,
-        client_response::Payload as ClientResponsePayload,
-    },
-    transport::expect_message,
+    transport::{Bi, expect_message},
+};
+use diesel::{
+    ExpressionMethods as _, OptionalExtension as _, QueryDsl as _, dsl::insert_into, update,
 };
-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::{
+        client::ClientConnection,
+        router::{self, RequestClientApproval},
+    },
     db::{self, 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")]
-    NotRegistered,
-    #[error("Internal error")]
-    InternalError,
+    #[error("Client approval request failed")]
+    ApproveError(#[from] ApproveError),
     #[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(router::ApprovalError),
+}
+
+#[derive(Debug, Clone)]
+pub enum Inbound {
+    AuthChallengeRequest { pubkey: VerifyingKey },
+    AuthChallengeSolution { signature: Signature },
+}
+
+#[derive(Debug, Clone)]
+pub enum Outbound {
+    AuthChallenge { pubkey: VerifyingKey, nonce: i32 },
+    AuthSuccess,
+}
+
 /// Atomically reads and increments the nonce for a known client.
 /// Returns `None` if the pubkey is not registered.
-async fn get_nonce(
-    db: &db::DatabasePool,
-    pubkey: &VerifyingKey,
-) -> Result<Option<(i32, i32)>, Error> {
+async fn get_nonce(db: &db::DatabasePool, pubkey: &VerifyingKey) -> Result<Option<i32>, Error> {
     let pubkey_bytes = pubkey.as_bytes().to_vec();
 
     let mut conn = db.get().await.map_err(|e| {
@@ -74,7 +83,8 @@ async fn get_nonce(
                 .execute(conn)
                 .await?;
 
-            Ok(Some((client_id, current_nonce)))
+            let _ = client_id;
+            Ok(Some(current_nonce))
         })
     })
     .await
@@ -84,47 +94,115 @@ async fn get_nonce(
     })
 }
 
-async fn challenge_client(
-    props: &mut ClientConnection,
+async fn approve_new_client(
+    actors: &crate::actors::GlobalActors,
+    pubkey: VerifyingKey,
+) -> Result<(), Error> {
+    let result = actors
+        .router
+        .ask(RequestClientApproval {
+            client_pubkey: pubkey,
+        })
+        .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 router failed");
+            Err(Error::ApproveError(ApproveError::Internal))
+        }
+    }
+}
+
+enum InsertClientResult {
+    Inserted,
+    AlreadyExists,
+}
+
+async fn insert_client(
+    db: &db::DatabasePool,
+    pubkey: &VerifyingKey,
+) -> Result<InsertClientResult, Error> {
+    let now = std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs() as i32;
+
+    let mut conn = db.get().await.map_err(|e| {
+        error!(error = ?e, "Database pool error");
+        Error::DatabasePoolUnavailable
+    })?;
+
+    match insert_into(program_client::table)
+        .values((
+            program_client::public_key.eq(pubkey.as_bytes().to_vec()),
+            program_client::nonce.eq(1), // pre-incremented; challenge uses 0
+            program_client::created_at.eq(now),
+            program_client::updated_at.eq(now),
+        ))
+        .execute(&mut conn)
+        .await
+    {
+        Ok(_) => {}
+        Err(diesel::result::Error::DatabaseError(
+            diesel::result::DatabaseErrorKind::UniqueViolation,
+            _,
+        )) => return Ok(InsertClientResult::AlreadyExists),
+        Err(e) => {
+            error!(error = ?e, "Failed to insert new client");
+            return Err(Error::DatabaseOperationFailed);
+        }
+    }
+
+    let client_id = program_client::table
+        .filter(program_client::public_key.eq(pubkey.as_bytes().to_vec()))
+        .order(program_client::id.desc())
+        .select(program_client::id)
+        .first::<i32>(&mut conn)
+        .await
+        .map_err(|e| {
+            error!(error = ?e, "Failed to load inserted client id");
+            Error::DatabaseOperationFailed
+        })?;
+
+    let _ = client_id;
+    Ok(InsertClientResult::Inserted)
+}
+
+async fn challenge_client<T>(
+    transport: &mut T,
     pubkey: VerifyingKey,
     nonce: i32,
-) -> Result<(), Error> {
-    let challenge = AuthChallenge {
-        pubkey: pubkey.as_bytes().to_vec(),
-        nonce,
-    };
-
-    props
-        .transport
-        .send(Ok(ClientResponse {
-            payload: Some(ClientResponsePayload::AuthChallenge(challenge.clone())),
-        }))
+) -> Result<(), Error>
+where
+    T: Bi<Inbound, Result<Outbound, Error>> + ?Sized,
+{
+    transport
+        .send(Ok(Outbound::AuthChallenge { pubkey, nonce }))
         .await
         .map_err(|e| {
             error!(error = ?e, "Failed to send auth challenge");
             Error::Transport
         })?;
 
-    let AuthChallengeSolution { signature } =
-        expect_message(&mut *props.transport, |req: ClientRequest| {
-            match req.payload? {
-                ClientRequestPayload::AuthChallengeSolution(s) => Some(s),
-                _ => None,
-            }
-        })
-        .await
-        .map_err(|e| {
-            error!(error = ?e, "Failed to receive challenge solution");
-            Error::Transport
-        })?;
-
-    let formatted = format_challenge(nonce, &challenge.pubkey);
-    let sig = signature.as_slice().try_into().map_err(|_| {
-        error!("Invalid signature length");
-        Error::InvalidChallengeSolution
+    let signature = expect_message(transport, |req: Inbound| match req {
+        Inbound::AuthChallengeSolution { signature } => Some(signature),
+        _ => None,
+    })
+    .await
+    .map_err(|e| {
+        error!(error = ?e, "Failed to receive challenge solution");
+        Error::Transport
     })?;
 
-    pubkey.verify_strict(&formatted, &sig).map_err(|_| {
+    let formatted = format_challenge(nonce, pubkey.as_bytes());
+
+    pubkey.verify_strict(&formatted, &signature).map_err(|_| {
         error!("Challenge solution verification failed");
         Error::InvalidChallengeSolution
     })?;
@@ -132,52 +210,40 @@ async fn challenge_client(
     Ok(())
 }
 
-fn connect_error_code(err: &Error) -> ConnectErrorCode {
-    match err {
-        Error::NotRegistered => ConnectErrorCode::ApprovalDenied,
-        _ => ConnectErrorCode::Unknown,
-    }
-}
-
-async fn authenticate(props: &mut ClientConnection) -> Result<(VerifyingKey, i32), Error> {
-    let Some(ClientRequest {
-        payload: Some(ClientRequestPayload::AuthChallengeRequest(challenge)),
-    }) = props.transport.recv().await
+pub async fn authenticate<T>(
+    props: &mut ClientConnection,
+    transport: &mut T,
+) -> Result<VerifyingKey, Error>
+where
+    T: Bi<Inbound, Result<Outbound, Error>> + Send + ?Sized,
+{
+    let Some(Inbound::AuthChallengeRequest { pubkey }) = transport.recv().await
     else {
         return Err(Error::Transport);
     };
 
-    let pubkey_bytes = challenge
-        .pubkey
-        .as_array()
-        .ok_or(Error::InvalidClientPubkeyLength)?;
-    let pubkey =
-        VerifyingKey::from_bytes(pubkey_bytes).map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
-
-    let (client_id, nonce) = match get_nonce(&props.db, &pubkey).await? {
-        Some((client_id, nonce)) => (client_id, nonce),
-        None => return Err(Error::NotRegistered),
+    let nonce = match get_nonce(&props.db, &pubkey).await? {
+        Some(nonce) => nonce,
+        None => {
+            approve_new_client(&props.actors, pubkey).await?;
+            match insert_client(&props.db, &pubkey).await? {
+                InsertClientResult::Inserted => 0,
+                InsertClientResult::AlreadyExists => match get_nonce(&props.db, &pubkey).await? {
+                    Some(nonce) => nonce,
+                    None => return Err(Error::DatabaseOperationFailed),
+                },
+            }
+        }
     };
 
-    challenge_client(props, pubkey, nonce).await?;
+    challenge_client(transport, pubkey, nonce).await?;
+    transport
+        .send(Ok(Outbound::AuthSuccess))
+        .await
+        .map_err(|e| {
+            error!(error = ?e, "Failed to send auth success");
+            Error::Transport
+        })?;
 
-    Ok((pubkey, client_id))
-}
-
-pub async fn authenticate_and_create(mut props: ClientConnection) -> Result<ClientSession, Error> {
-    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)
-        }
-    }
+    Ok(pubkey)
 }

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

@@ -1,7 +1,4 @@
-use arbiter_proto::{
-    proto::client::{ClientRequest, ClientResponse},
-    transport::Bi,
-};
+use arbiter_proto::transport::Bi;
 use kameo::actor::Spawn;
 use tracing::{error, info};
 
@@ -10,48 +7,31 @@ use crate::{
     db,
 };
 
-#[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
-pub enum ClientError {
-    #[error("Expected message with payload")]
-    MissingRequestPayload,
-    #[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 {
-        Self {
-            db,
-            transport,
-            actors,
-        }
+    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
+        Self { db, actors }
     }
 }
 
 pub mod auth;
 pub mod session;
 
-pub async fn connect_client(props: ClientConnection) {
-    match auth::authenticate_and_create(props).await {
-        Ok(session) => {
-            ClientSession::spawn(session);
+pub async fn connect_client<T>(mut props: ClientConnection, transport: &mut T)
+where
+    T: Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> + Send + ?Sized,
+{
+    match auth::authenticate(&mut props, transport).await {
+        Ok(_pubkey) => {
+            ClientSession::spawn(ClientSession::new(props));
             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

@@ -1,92 +1,45 @@
-use alloy::{consensus::TxEip1559, primitives::Address, rlp::Decodable};
-use arbiter_proto::proto::{
-    client::{
-        ClientRequest, ClientResponse, client_request::Payload as ClientRequestPayload,
-        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 kameo::{Actor, messages};
+use tracing::error;
 
 use crate::{
     actors::{
-        GlobalActors,
-        client::{ClientConnection, ClientError},
-        evm::ClientSignTransaction,
-        router::RegisterClient,
+        GlobalActors, client::ClientConnection, keyholder::KeyHolderState, router::RegisterClient,
     },
     db,
 };
 
 pub struct ClientSession {
     props: ClientConnection,
-    client_id: i32,
 }
 
 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 {
-        let msg = req.payload.ok_or_else(|| {
-            error!(actor = "client", "Received message with no payload");
-            ClientError::MissingRequestPayload
-        })?;
-
-        match msg {
-            ClientRequestPayload::EvmSignTransaction(sign_req) => {
-                let wallet_address: [u8; 20] = sign_req
-                    .wallet_address
-                    .try_into()
-                    .map_err(|_| ClientError::UnexpectedRequestPayload)?;
-
-                let mut rlp_bytes: &[u8] = &sign_req.rlp_transaction;
-                let tx = TxEip1559::decode(&mut rlp_bytes)
-                    .map_err(|_| ClientError::UnexpectedRequestPayload)?;
-
-                let result = self
-                    .props
-                    .actors
-                    .evm
-                    .ask(ClientSignTransaction {
-                        client_id: self.client_id,
-                        wallet_address: Address::from_slice(&wallet_address),
-                        transaction: tx,
-                    })
-                    .await;
-
-                let response_result = match result {
-                    Ok(signature) => SignResult::Signature(signature.as_bytes().to_vec()),
-                    Err(err) => {
-                        error!(?err, "client sign transaction failed");
-                        SignResult::Error(EvmError::Internal.into())
-                    }
-                };
-
-                Ok(ClientResponse {
-                    payload: Some(ClientResponsePayload::EvmSignTransaction(
-                        EvmSignTransactionResponse {
-                            result: Some(response_result),
-                        },
-                    )),
-                })
-            }
-            _ => Err(ClientError::UnexpectedRequestPayload),
-        }
+    pub(crate) fn new(props: ClientConnection) -> Self {
+        Self { props }
     }
 }
 
-type Output = Result<ClientResponse, ClientError>;
+#[messages]
+impl ClientSession {
+    #[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 = "client", "keyholder.query.failed");
+                return Err(Error::Internal);
+            }
+        };
+
+        Ok(vault_state)
+    }
+}
 
 impl Actor for ClientSession {
     type Args = Self;
 
-    type Error = ClientError;
+    type Error = Error;
 
     async fn on_start(
         args: Self::Args,
@@ -97,55 +50,22 @@ impl Actor for ClientSession {
             .router
             .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 transport: super::Transport = Box::new(DummyTransport::new());
-        let props = ClientConnection::new(db, transport, actors);
-        Self {
-            props,
-            client_id: 0,
-        }
+        let props = ClientConnection::new(db, actors);
+        Self { props }
     }
 }
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Connection registration failed")]
+    ConnectionRegistrationFailed,
+    #[error("Internal error")]
+    Internal,
+}

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

@@ -1,21 +1,26 @@
 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::{
+        self, DatabasePool,
+        models::{self, SqliteTimestamp},
+        schema,
+    },
     evm::{
-        self, RunKind,
+        self, ListGrantsError, RunKind,
         policies::{
-            FullGrant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
-            ether_transfer::EtherTransfer,
-            token_transfers::TokenTransfer,
+            FullGrant, Grant, SharedGrantSettings, SpecificGrant, SpecificMeaning,
+            ether_transfer::EtherTransfer, token_transfers::TokenTransfer,
         },
     },
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 
 pub use crate::evm::safe_signer;
@@ -88,7 +93,12 @@ 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,
+        }
     }
 }
 
@@ -98,11 +108,7 @@ impl EvmActor {
     pub async fn generate(&mut self) -> Result<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 = {
-            let reader = key_cell.read().expect("MemSafe read");
-            MemSafe::new(reader.to_vec()).expect("MemSafe allocation")
-        };
+        let plaintext = key_cell.read_inline(|reader| SafeCell::new(reader.to_vec()));
 
         let aead_id: i32 = self
             .keyholder
@@ -149,12 +155,24 @@ impl EvmActor {
         match grant {
             SpecificGrant::EtherTransfer(settings) => {
                 self.engine
-                    .create_grant::<EtherTransfer>(client_id, FullGrant { basic, specific: settings })
+                    .create_grant::<EtherTransfer>(
+                        client_id,
+                        FullGrant {
+                            basic,
+                            specific: settings,
+                        },
+                    )
                     .await
             }
             SpecificGrant::TokenTransfer(settings) => {
                 self.engine
-                    .create_grant::<TokenTransfer>(client_id, FullGrant { basic, specific: settings })
+                    .create_grant::<TokenTransfer>(
+                        client_id,
+                        FullGrant {
+                            basic,
+                            specific: settings,
+                        },
+                    )
                     .await
             }
         }
@@ -172,19 +190,12 @@ impl EvmActor {
     }
 
     #[message]
-    pub async fn useragent_list_grants(
-        &mut self,
-        wallet_id: Option<i32>,
-    ) -> Result<Vec<EvmBasicGrant>, Error> {
-        let mut conn = self.db.get().await?;
-        let mut query = schema::evm_basic_grant::table
-            .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));
+    pub async fn useragent_list_grants(&mut self) -> Result<Vec<Grant<SpecificGrant>>, Error> {
+        match self.engine.list_all_grants().await {
+            Ok(grants) => Ok(grants),
+            Err(ListGrantsError::Database(db)) => Err(Error::Database(db)),
+            Err(ListGrantsError::Pool(pool)) => Err(Error::DatabasePool(pool)),
         }
-        Ok(query.load(&mut conn).await?)
     }
 
     #[message]
@@ -204,8 +215,14 @@ impl EvmActor {
             .ok_or(SignTransactionError::WalletNotFound)?;
         drop(conn);
 
-        let meaning = self.engine
-            .evaluate_transaction(wallet.id, client_id, transaction.clone(), RunKind::Execution)
+        let meaning = self
+            .engine
+            .evaluate_transaction(
+                wallet.id,
+                client_id,
+                transaction.clone(),
+                RunKind::Execution,
+            )
             .await?;
 
         Ok(meaning)
@@ -228,16 +245,23 @@ impl EvmActor {
             .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.id,
+                client_id,
+                transaction.clone(),
+                RunKind::Execution,
+            )
             .await?;
 
         use alloy::network::TxSignerSync as _;

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

@@ -5,12 +5,13 @@ use chacha20poly1305::{
     AeadInPlace, Key, KeyInit as _, XChaCha20Poly1305, XNonce,
     aead::{AeadMut, Error, Payload},
 };
-use memsafe::MemSafe;
 use rand::{
     Rng as _, SeedableRng,
     rngs::{StdRng, SysRng},
 };
 
+use crate::safe_cell::{SafeCell, SafeCellHandle as _};
+
 pub const ROOT_KEY_TAG: &[u8] = "arbiter/seal/v1".as_bytes();
 pub const TAG: &[u8] = "arbiter/private-key/v1".as_bytes();
 
@@ -47,40 +48,37 @@ impl<'a> TryFrom<&'a [u8]> for Nonce {
     }
 }
 
-pub struct KeyCell(pub MemSafe<Key>);
-impl From<MemSafe<Key>> for KeyCell {
-    fn from(value: MemSafe<Key>) -> Self {
+pub struct KeyCell(pub SafeCell<Key>);
+impl From<SafeCell<Key>> for KeyCell {
+    fn from(value: SafeCell<Key>) -> Self {
         Self(value)
     }
 }
-impl TryFrom<MemSafe<Vec<u8>>> for KeyCell {
+impl TryFrom<SafeCell<Vec<u8>>> for KeyCell {
     type Error = ();
 
-    fn try_from(mut value: MemSafe<Vec<u8>>) -> Result<Self, Self::Error> {
-        let value = value.read().unwrap();
+    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 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);
-        }
+        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 mut key = MemSafe::new(Key::default()).unwrap();
-        {
-            let mut key_buffer = key.write().unwrap();
-            let key_buffer: &mut [u8] = key_buffer.as_mut();
-
+        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()
     }
@@ -91,7 +89,7 @@ impl KeyCell {
         associated_data: &[u8],
         mut buffer: impl AsMut<Vec<u8>>,
     ) -> Result<(), Error> {
-        let key_reader = self.0.read().unwrap();
+        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());
@@ -102,13 +100,13 @@ impl KeyCell {
         &mut self,
         nonce: &Nonce,
         associated_data: &[u8],
-        buffer: &mut MemSafe<Vec<u8>>,
+        buffer: &mut SafeCell<Vec<u8>>,
     ) -> Result<(), Error> {
-        let key_reader = self.0.read().unwrap();
+        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().unwrap();
+        let mut buffer = buffer.write();
         let buffer: &mut Vec<u8> = buffer.as_mut();
         cipher.decrypt_in_place(nonce, associated_data, buffer)
     }
@@ -119,7 +117,7 @@ impl KeyCell {
         associated_data: &[u8],
         plaintext: impl AsRef<[u8]>,
     ) -> Result<Vec<u8>, Error> {
-        let key_reader = self.0.read().unwrap();
+        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());
@@ -139,6 +137,10 @@ 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
@@ -146,19 +148,23 @@ pub fn generate_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 {
+pub fn derive_seal_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 = MemSafe::new(Key::default()).unwrap();
-    {
-        let password_source = password.read().unwrap();
-        let mut key_buffer = key.write().unwrap();
+    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()
 }
@@ -166,20 +172,20 @@ pub fn derive_seal_key(mut password: MemSafe<Vec<u8>>, salt: &Salt) -> KeyCell {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use memsafe::MemSafe;
+    use crate::safe_cell::SafeCell;
 
     #[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 password = SafeCell::new(PASSWORD.to_vec());
+        let password2 = SafeCell::new(PASSWORD.to_vec());
         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();
+        let key1_reader = key1.0.read();
+        let key2_reader = key2.0.read();
 
         assert_eq!(key1_reader.deref(), key2_reader.deref());
     }
@@ -187,11 +193,11 @@ mod tests {
     #[test]
     pub fn successful_derive() {
         static PASSWORD: &[u8] = b"password";
-        let password = MemSafe::new(PASSWORD.to_vec()).unwrap();
+        let password = SafeCell::new(PASSWORD.to_vec());
         let salt = generate_salt();
 
         let mut key = derive_seal_key(password, &salt);
-        let key_reader = key.0.read().unwrap();
+        let key_reader = key.0.read();
         let key_ref = key_reader.deref();
 
         assert_ne!(key_ref.as_slice(), &[0u8; 32][..]);
@@ -200,7 +206,7 @@ mod tests {
     #[test]
     pub fn encrypt_decrypt() {
         static PASSWORD: &[u8] = b"password";
-        let password = MemSafe::new(PASSWORD.to_vec()).unwrap();
+        let password = SafeCell::new(PASSWORD.to_vec());
         let salt = generate_salt();
 
         let mut key = derive_seal_key(password, &salt);
@@ -212,12 +218,12 @@ mod tests {
             .unwrap();
         assert_ne!(buffer, b"secret data");
 
-        let mut buffer = MemSafe::new(buffer).unwrap();
+        let mut buffer = SafeCell::new(buffer);
 
         key.decrypt_in_place(&nonce, associated_data, &mut buffer)
             .unwrap();
 
-        let buffer = buffer.read().unwrap();
+        let buffer = buffer.read();
         assert_eq!(*buffer, b"secret data");
     }
 

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

@@ -5,21 +5,24 @@ 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::{
-    self,
-    models::{self, RootKeyHistory},
-    schema::{self},
+use crate::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,
@@ -136,7 +139,7 @@ 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);
         }
@@ -148,16 +151,15 @@ impl KeyHolder {
         let root_key_nonce = v1::Nonce::default();
         let data_encryption_nonce = v1::Nonce::default();
 
-        let root_key_ciphertext: Vec<u8> = {
-            let root_key_reader = root_key.0.read().unwrap();
-            let root_key_reader = root_key_reader.as_slice();
+        let root_key_ciphertext: Vec<u8> = root_key.0.read_inline(|reader| {
+            let root_key_reader = 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 +201,7 @@ 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
@@ -225,7 +227,7 @@ impl KeyHolder {
         })?;
         let mut seal_key = v1::derive_seal_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(
             |_| {
@@ -256,7 +258,7 @@ impl KeyHolder {
 
     // Decrypts the `aead_encrypted` entry with the given ID and returns the plaintext
     #[message]
-    pub async fn decrypt(&mut self, aead_id: i32) -> Result<MemSafe<Vec<u8>>, Error> {
+    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);
         };
@@ -279,14 +281,14 @@ 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,
@@ -299,7 +301,7 @@ 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 +315,7 @@ 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 +325,7 @@ impl KeyHolder {
     }
 
     #[message]
-    pub fn get_state(&self) -> StateDiscriminants {
+    pub fn get_state(&self) -> KeyHolderState {
         self.state.discriminant()
     }
 
@@ -348,15 +350,17 @@ 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 +395,7 @@ 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/router/mod.rs

@@ -1,14 +1,20 @@
 use std::{collections::HashMap, ops::ControlFlow};
 
+use ed25519_dalek::VerifyingKey;
 use kameo::{
     Actor,
     actor::{ActorId, ActorRef},
     messages,
     prelude::{ActorStopReason, Context, WeakActorRef},
+    reply::DelegatedReply,
 };
-use tracing::info;
+use tokio::{sync::watch, task::JoinSet};
+use tracing::{info, warn};
 
-use crate::actors::{client::session::ClientSession, user_agent::session::UserAgentSession};
+use crate::actors::{
+    client::session::ClientSession,
+    user_agent::session::{RequestNewClientApproval, UserAgentSession},
+};
 
 #[derive(Default)]
 pub struct MessageRouter {
@@ -50,6 +56,73 @@ impl Actor for MessageRouter {
     }
 }
 
+#[derive(Debug, thiserror::Error, Clone, PartialEq, Eq, Hash)]
+pub enum ApprovalError {
+    #[error("No user agents connected")]
+    NoUserAgentsConnected,
+}
+
+async fn request_client_approval(
+    user_agents: &[WeakActorRef<UserAgentSession>],
+    client_pubkey: VerifyingKey,
+) -> Result<bool, ApprovalError> {
+    if user_agents.is_empty() {
+        return Err(ApprovalError::NoUserAgentsConnected);
+    }
+
+    let mut pool = JoinSet::new();
+    let (cancel_tx, cancel_rx) = watch::channel(());
+
+    for weak_ref in user_agents {
+        match weak_ref.upgrade() {
+            Some(agent) => {
+                let cancel_rx = cancel_rx.clone();
+                pool.spawn(async move {
+                    agent
+                        .ask(RequestNewClientApproval {
+                            client_pubkey,
+                            cancel_flag: cancel_rx.clone(),
+                        })
+                        .await
+                });
+            }
+            None => {
+                warn!(
+                    id = weak_ref.id().to_string(),
+                    actor = "MessageRouter",
+                    event = "useragent.disconnected_before_approval"
+                );
+            }
+        }
+    }
+
+    while let Some(result) = pool.join_next().await {
+        match result {
+            Ok(Ok(approved)) => {
+                // cancel other pending requests
+                let _ = cancel_tx.send(());
+                return Ok(approved);
+            }
+            Ok(Err(err)) => {
+                warn!(
+                    ?err,
+                    actor = "MessageRouter",
+                    event = "useragent.approval_error"
+                );
+            }
+            Err(err) => {
+                warn!(
+                    ?err,
+                    actor = "MessageRouter",
+                    event = "useragent.approval_task_failed"
+                );
+            }
+        }
+    }
+
+    Err(ApprovalError::NoUserAgentsConnected)
+}
+
 #[messages]
 impl MessageRouter {
     #[message(ctx)]
@@ -73,4 +146,28 @@ impl MessageRouter {
         ctx.actor_ref().link(&actor).await;
         self.clients.insert(actor.id(), actor);
     }
+
+    #[message(ctx)]
+    pub async fn request_client_approval(
+        &mut self,
+        client_pubkey: VerifyingKey,
+        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 weak_refs = self
+            .user_agents
+            .values()
+            .map(|agent| agent.downgrade())
+            .collect::<Vec<_>>();
+
+        tokio::task::spawn(async move {
+            let result = request_client_approval(&weak_refs, client_pubkey).await;
+            reply_sender.send(result);
+        });
+
+        reply
+    }
 }

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

@@ -1,114 +1,82 @@
-use arbiter_proto::proto::user_agent::{
-    AuthChallengeRequest, AuthChallengeSolution, KeyType as ProtoKeyType, UserAgentRequest,
-    user_agent_request::Payload as UserAgentRequestPayload,
-};
+use arbiter_proto::transport::Bi;
 use tracing::error;
 
 use crate::actors::user_agent::{
-    UserAgentConnection,
-    auth::state::{AuthContext, AuthPublicKey, AuthStateMachine},
-    session::UserAgentSession,
+    AuthPublicKey, UserAgentConnection,
+    auth::state::{AuthContext, AuthStateMachine},
 };
 
-#[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> {
-    match key_type {
-        // UNSPECIFIED treated as Ed25519 for backward compatibility
-        ProtoKeyType::Unspecified | ProtoKeyType::Ed25519 => {
-            let pubkey_bytes = pubkey.as_array().ok_or(Error::InvalidClientPubkeyLength)?;
-            let key = ed25519_dalek::VerifyingKey::from_bytes(pubkey_bytes)
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
-            Ok(AuthPublicKey::Ed25519(key))
-        }
-        ProtoKeyType::EcdsaSecp256k1 => {
-            // Public key is sent as 33-byte SEC1 compressed point
-            let key = k256::ecdsa::VerifyingKey::from_sec1_bytes(&pubkey)
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
-            Ok(AuthPublicKey::EcdsaSecp256k1(key))
-        }
-        ProtoKeyType::Rsa => {
-            use rsa::pkcs8::DecodePublicKey as _;
-            let key = rsa::RsaPublicKey::from_public_key_der(&pubkey)
-                .map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
-            Ok(AuthPublicKey::Rsa(key))
+#[derive(Debug, Clone)]
+pub enum Inbound {
+    AuthChallengeRequest {
+        pubkey: AuthPublicKey,
+        bootstrap_token: Option<String>,
+    },
+    AuthChallengeSolution {
+        signature: Vec<u8>,
+    },
+}
+
+#[derive(Debug)]
+pub enum Error {
+    UnregisteredPublicKey,
+    InvalidChallengeSolution,
+    InvalidBootstrapToken,
+    Internal { details: String },
+    Transport,
+}
+
+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,
-        }) => {
-            let kt = ProtoKeyType::try_from(key_type).unwrap_or(ProtoKeyType::Unspecified);
-            Ok(AuthEvents::AuthRequest(ChallengeRequest {
-                pubkey: parse_pubkey(kt, pubkey)?,
-            }))
-        }
-        UserAgentRequestPayload::AuthChallengeRequest(AuthChallengeRequest {
+        } => AuthEvents::AuthRequest(ChallengeRequest { pubkey }),
+        Inbound::AuthChallengeRequest {
             pubkey,
             bootstrap_token: Some(token),
-            key_type,
-        }) => {
-            let kt = ProtoKeyType::try_from(key_type).unwrap_or(ProtoKeyType::Unspecified);
-            Ok(AuthEvents::BootstrapAuthRequest(BootstrapAuthRequest {
-                pubkey: parse_pubkey(kt, pubkey)?,
-                token,
-            }))
-        }
-        UserAgentRequestPayload::AuthChallengeSolution(AuthChallengeSolution { signature }) => {
-            Ok(AuthEvents::ReceivedSolution(ChallengeSolution {
+        } => AuthEvents::BootstrapAuthRequest(BootstrapAuthRequest { pubkey, token }),
+        Inbound::AuthChallengeSolution { signature } => {
+            AuthEvents::ReceivedSolution(ChallengeSolution {
                 solution: signature,
-            }))
+            })
         }
-        _ => Err(Error::UnexpectedMessagePayload),
     }
 }
 
-pub async fn authenticate(props: &mut UserAgentConnection) -> Result<AuthPublicKey, Error> {
-    let mut state = AuthStateMachine::new(AuthContext::new(props));
+pub async fn authenticate<T>(
+    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(UserAgentRequest {
-            payload: Some(payload),
-        }) = transport.recv().await
-        else {
+        let Some(payload) = state.context_mut().transport.recv().await else {
             return Err(Error::Transport);
         };
 
-        let event = parse_auth_event(payload)?;
-
-        match state.process_event(event).await {
+        match state.process_event(parse_auth_event(payload)).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

@@ -1,52 +1,17 @@
-use arbiter_proto::proto::user_agent::{
-    AuthChallenge, UserAgentResponse, user_agent_response::Payload as UserAgentResponsePayload,
-};
+use arbiter_proto::transport::Bi;
 use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, update};
 use diesel_async::RunQueryDsl;
 use tracing::error;
 
 use super::Error;
 use crate::{
-    actors::{bootstrap::ConsumeToken, user_agent::UserAgentConnection},
-    db::{models::KeyType, schema},
+    actors::{
+        bootstrap::ConsumeToken,
+        user_agent::{AuthPublicKey, UserAgentConnection, auth::Outbound},
+    },
+    db::schema,
 };
 
-/// Abstraction over Ed25519 / ECDSA-secp256k1 / RSA public keys used during the auth handshake.
-#[derive(Clone)]
-pub enum AuthPublicKey {
-    Ed25519(ed25519_dalek::VerifyingKey),
-    /// Compressed SEC1 public key; signature bytes are raw 64-byte (r||s).
-    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 {
     pub pubkey: AuthPublicKey,
 }
@@ -57,7 +22,7 @@ pub struct BootstrapAuthRequest {
 }
 
 pub struct ChallengeContext {
-    pub challenge: AuthChallenge,
+    pub challenge_nonce: i32,
     pub key: AuthPublicKey,
 }
 
@@ -70,15 +35,15 @@ 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),
-        SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) [async verify_solution] / provide_key = AuthOk(AuthPublicKey),
+        Init + BootstrapAuthRequest(BootstrapAuthRequest) / async verify_bootstrap_token = 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> {
     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| {
@@ -102,11 +67,11 @@ 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
         })
 }
 
@@ -115,7 +80,7 @@ async fn register_key(db: &crate::db::DatabasePool, pubkey: &AuthPublicKey) -> R
     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)
@@ -128,31 +93,95 @@ async fn register_key(db: &crate::db::DatabasePool, pubkey: &AuthPublicKey) -> R
         .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> {
-    pub fn new(conn: &'a mut UserAgentConnection) -> Self {
-        Self { conn }
+impl<'a, T> AuthContext<'a, T> {
+    pub fn new(conn: &'a mut UserAgentConnection, transport: T) -> Self {
+        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> {
+        let stored_bytes = pubkey.to_stored_bytes();
+        let nonce = create_nonce(&self.conn.db, &stored_bytes).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);
+        }
+
+        register_key(&self.conn.db, &pubkey).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,
-        ChallengeContext { challenge, key }: &ChallengeContext,
-        ChallengeSolution { solution }: &ChallengeSolution,
-    ) -> Result<bool, Self::Error> {
-        let formatted = arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
+        &mut self,
+        ChallengeContext {
+            challenge_nonce,
+            key,
+        }: &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 +210,13 @@ impl AuthStateMachineContext for AuthContext<'_> {
             }
         };
 
-        Ok(valid)
-    }
-
-    async fn prepare_challenge(
-        &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| {
-                error!(?e, "Failed to send auth challenge");
-                Error::Transport
-            })?;
-
-        Ok(ChallengeContext {
-            challenge,
-            key: pubkey,
-        })
-    }
-
-    #[allow(missing_docs)]
-    #[allow(clippy::result_unit_err)]
-    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| {
-                error!(?e, "Failed to consume bootstrap token");
-                Error::BootstrapperActorUnreachable
-            })?;
-
-        if !token_ok {
-            error!("Invalid bootstrap token provided");
-            return Err(Error::InvalidBootstrapToken);
+        if valid {
+            self.transport
+                .send(Ok(Outbound::AuthSuccess))
+                .await
+                .map_err(|_| Error::Transport)?;
         }
 
-        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)
+        Ok(key.clone())
     }
 }

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},
-    db::{self},
+    actors::GlobalActors,
+    db::{self, models::KeyType},
 };
 
-#[derive(Debug, thiserror::Error, PartialEq)]
-pub enum TransportResponseError {
-    #[error("Expected message with payload")]
-    MissingRequestPayload,
-    #[error("Unexpected request payload")]
-    UnexpectedRequestPayload,
-    #[error("Invalid state for unseal encrypted key")]
-    InvalidStateForUnsealEncryptedKey,
-    #[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,
+/// Abstraction over Ed25519 / ECDSA-secp256k1 / RSA public keys used during the auth handshake.
+#[derive(Clone, Debug)]
+pub enum AuthPublicKey {
+    Ed25519(ed25519_dalek::VerifyingKey),
+    /// Compressed SEC1 public key; signature bytes are raw 64-byte (r||s).
+    EcdsaSecp256k1(k256::ecdsa::VerifyingKey),
+    /// RSA-2048+ public key (Windows Hello / KeyCredentialManager); signature bytes are PSS+SHA-256.
+    Rsa(rsa::RsaPublicKey),
 }
 
-pub type Transport =
-    Box<dyn Bi<UserAgentRequest, Result<UserAgentResponse, TransportResponseError>> + Send>;
+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 _;
+                #[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 { pubkey: ed25519_dalek::VerifyingKey },
+    ClientConnectionCancel,
+}
 
 pub struct UserAgentConnection {
-    db: db::DatabasePool,
-    actors: GlobalActors,
-    transport: Transport,
+    pub(crate) db: db::DatabasePool,
+    pub(crate) actors: GlobalActors,
 }
 
 impl UserAgentConnection {
-    pub fn new(db: db::DatabasePool, actors: GlobalActors, transport: Transport) -> Self {
-        Self {
-            db,
-            actors,
-            transport,
-        }
+    pub fn new(db: db::DatabasePool, actors: GlobalActors) -> Self {
+        Self { db, actors }
     }
 }
 
 pub mod auth;
 pub mod session;
 
-pub async fn connect_user_agent(props: UserAgentConnection) {
-    match auth::authenticate_and_create(props).await {
-        Ok(session) => {
-            UserAgentSession::spawn(session);
-            info!("User authenticated, session started");
-        }
-        Err(err) => {
-            error!(?err, "Authentication failed, closing connection");
-        }
-    }
-}
+pub use auth::authenticate;
+pub use session::UserAgentSession;

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

@@ -1,523 +1,116 @@
-use std::{ops::DerefMut, sync::Mutex};
+use std::borrow::Cow;
 
-use arbiter_proto::proto::{
-    evm as evm_proto,
-    user_agent::{
-        SdkClientApproveRequest, SdkClientApproveResponse, SdkClientEntry,
-        SdkClientError as ProtoSdkClientError, SdkClientList, SdkClientListResponse,
-        SdkClientRevokeRequest, SdkClientRevokeResponse, UnsealEncryptedKey, UnsealResult,
-        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 arbiter_proto::transport::Sender;
+use async_trait::async_trait;
+use ed25519_dalek::VerifyingKey;
+use kameo::{Actor, messages};
+use thiserror::Error;
+use tokio::sync::watch;
+use tracing::error;
 
-use crate::{
-    actors::{
-        evm::{Generate, ListWallets},
-        keyholder::{self, TryUnseal},
-        router::RegisterUserAgent,
-        user_agent::{TransportResponseError, UserAgentConnection},
-    },
-    db::schema::program_client,
+use crate::actors::{
+    router::RegisterUserAgent,
+    user_agent::{OutOfBand, UserAgentConnection},
 };
 
 mod state;
-use state::{DummyContext, UnsealContext, UserAgentEvents, UserAgentStateMachine, UserAgentStates};
+use state::{DummyContext, UserAgentEvents, UserAgentStateMachine};
 
-// Error for consumption by other actors
-#[derive(Debug, thiserror::Error, PartialEq)]
+#[derive(Debug, Error)]
 pub enum Error {
-    #[error("User agent session ended due to connection loss")]
-    ConnectionLost,
+    #[error("State transition failed")]
+    State,
 
-    #[error("User agent session ended due to unexpected message")]
-    UnexpectedMessage,
+    #[error("Internal error: {message}")]
+    Internal { message: Cow<'static, str> },
+}
+
+impl Error {
+    pub fn internal(message: impl Into<Cow<'static, str>>) -> Self {
+        Self::Internal {
+            message: message.into(),
+        }
+    }
 }
 
 pub struct UserAgentSession {
     props: UserAgentConnection,
     state: UserAgentStateMachine<DummyContext>,
+    #[allow(dead_code, reason = "The session keeps ownership of the outbound transport even before the state-machine flow starts using it directly")]
+    sender: Box<dyn Sender<OutOfBand>>,
 }
 
+mod connection;
+pub(crate) use connection::{
+    BootstrapError, HandleBootstrapEncryptedKey, HandleEvmWalletCreate, HandleEvmWalletList,
+    HandleGrantCreate, HandleGrantDelete, HandleGrantList, HandleQueryVaultState,
+};
+pub use connection::{HandleUnsealEncryptedKey, HandleUnsealRequest, UnsealError};
+
 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,
         }
     }
 
-    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 request_new_client_approval(
         &mut self,
-        msg: UserAgentResponsePayload,
-        _ctx: &mut Context<Self, Reply>,
-    ) -> Result<(), Error> {
-        self.props
-            .transport
-            .send(Ok(response(msg)))
-            .await
-            .map_err(|_| {
-                error!(
-                    actor = "useragent",
-                    reason = "channel closed",
-                    "send.failed"
-                );
-                Error::ConnectionLost
+        client_pubkey: VerifyingKey,
+        mut cancel_flag: watch::Receiver<()>,
+    ) -> Result<bool, ()> {
+        if self
+            .sender
+            .send(OutOfBand::ClientConnectionRequest {
+                pubkey: client_pubkey,
             })
-    }
-
-    async fn expect_msg<Extractor, Msg, Reply>(
-        &mut self,
-        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
+            .is_err()
         {
-            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(),
-                        )),
-                    },
-                )))
-            }
+            return Err(());
         }
-    }
 
-    async fn handle_sdk_client_revoke(&mut self, req: SdkClientRevokeRequest) -> Output {
-        use sdk_client_revoke_response::Result as RevokeResult;
+        let _ = cancel_flag.changed().await;
 
-        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
-        }
+        let _ = self.sender.send(OutOfBand::ClientConnectionCancel).await;
+        Ok(false)
     }
 }
 
 impl Actor for UserAgentSession {
     type Args = Self;
 
-    type Error = TransportResponseError;
+    type Error = Error;
 
     async fn on_start(
         args: Self::Args,
@@ -532,56 +125,8 @@ impl Actor for UserAgentSession {
             .await
             .map_err(|err| {
                 error!(?err, "Failed to register user agent connection with router");
-                TransportResponseError::ConnectionRegistrationFailed
+                Error::internal("Failed to register user agent connection with router")
             })?;
         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(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 {
-    pub fn new_test(db: crate::db::DatabasePool, actors: crate::actors::GlobalActors) -> Self {
-        use arbiter_proto::transport::DummyTransport;
-        let transport: super::Transport = Box::new(DummyTransport::new());
-        let props = UserAgentConnection::new(db, actors, transport);
-        Self {
-            props,
-            state: UserAgentStateMachine::new(DummyContext),
-        }
-    }
 }

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

@@ -0,0 +1,354 @@
+use std::sync::Mutex;
+
+use alloy::primitives::Address;
+use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
+use kameo::error::SendError;
+use kameo::messages;
+use tracing::{error, info};
+use x25519_dalek::{EphemeralSecret, PublicKey};
+
+use crate::actors::keyholder::KeyHolderState;
+use crate::actors::user_agent::session::Error;
+use crate::evm::policies::{Grant, SpecificGrant};
+use crate::safe_cell::SafeCell;
+use crate::{
+    actors::{
+        evm::{
+            Generate, ListWallets, 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),
+}
+
+#[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<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<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,
+        client_id: i32,
+        basic: crate::evm::policies::SharedGrantSettings,
+        grant: crate::evm::policies::SpecificGrant,
+    ) -> Result<i32, Error> {
+        match self
+            .props
+            .actors
+            .evm
+            .ask(UseragentCreateGrant {
+                client_id,
+                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"))
+            }
+        }
+    }
+}

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

@@ -8,7 +8,7 @@ use rcgen::{
     BasicConstraints, Certificate, CertificateParams, CertifiedIssuer, DistinguishedName, DnType,
     IsCa, Issuer, KeyPair, KeyUsagePurpose,
 };
-use rustls::pki_types::{pem::PemObject};
+use rustls::pki_types::pem::PemObject;
 use thiserror::Error;
 use tonic::transport::CertificateDer;
 
@@ -59,10 +59,7 @@ pub enum InitError {
 pub type PemCert = String;
 
 pub fn encode_cert_to_pem(cert: &CertificateDer) -> PemCert {
-    pem::encode_config(
-        &Pem::new("CERTIFICATE", cert.to_vec()),
-        ENCODE_CONFIG,
-    )
+    pem::encode_config(&Pem::new("CERTIFICATE", cert.to_vec()), ENCODE_CONFIG)
 }
 
 #[allow(unused)]
@@ -94,6 +91,10 @@ 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(),

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

@@ -44,6 +44,14 @@ pub enum DatabaseSetupError {
     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 +100,7 @@ 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 +144,13 @@ 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/evm/mod.rs

@@ -117,9 +117,7 @@ async fn check_shared_constraints(
     let now = Utc::now();
 
     // Validity window
-    if shared.valid_from.is_some_and(|t| now < t)
-        || shared.valid_until.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) {
         violations.push(EvalViolation::InvalidTime);
     }
 
@@ -127,9 +125,9 @@ 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| {
-        U256::from(context.max_priority_fee_per_gas) > cap
-    });
+    let priority_exceeded = shared
+        .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,

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

@@ -66,6 +66,7 @@ pub enum EvalViolation {
 
 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 +74,6 @@ 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>;
@@ -146,6 +146,7 @@ pub struct VolumeRateLimit {
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct SharedGrantSettings {
     pub wallet_id: i32,
+    pub client_id: i32,
     pub chain: ChainId,
 
     pub valid_from: Option<DateTime<Utc>>,
@@ -161,6 +162,7 @@ impl SharedGrantSettings {
     fn try_from_model(model: EvmBasicGrant) -> QueryResult<Self> {
         Ok(Self {
             wallet_id: model.wallet_id,
+            client_id: model.client_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 +200,7 @@ 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

@@ -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>,
-    limit: VolumeRateLimit,
+    pub target: Vec<Address>,
+    pub limit: VolumeRateLimit,
 }
 
 impl From<Settings> for SpecificGrant {

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

@@ -9,9 +9,7 @@ use crate::db::{
     schema::{evm_basic_grant, evm_transaction_log},
 };
 use crate::evm::{
-    policies::{
-        EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit,
-    },
+    policies::{EvalContext, EvalViolation, Grant, Policy, SharedGrantSettings, VolumeRateLimit},
     utils,
 };
 
@@ -76,6 +74,7 @@ fn shared() -> SharedGrantSettings {
         max_gas_fee_per_gas: None,
         max_priority_fee_per_gas: None,
         rate_limit: None,
+        client_id: CLIENT_ID,
     }
 }
 

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

@@ -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,
-    target: Option<Address>,
-    volume_limits: Vec<VolumeRateLimit>,
+    pub token_contract: Address,
+    pub target: Option<Address>,
+    pub volume_limits: Vec<VolumeRateLimit>,
 }
 impl From<Settings> for SpecificGrant {
     fn from(val: Settings) -> SpecificGrant {

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

@@ -93,6 +93,7 @@ fn shared() -> SharedGrantSettings {
         max_gas_fee_per_gas: None,
         max_priority_fee_per_gas: None,
         rate_limit: None,
+        client_id: CLIENT_ID,
     }
 }
 
@@ -140,10 +141,18 @@ 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).await.unwrap();
-    assert!(v.iter().any(|e| matches!(e, EvalViolation::InvalidTransactionType)));
+    assert!(
+        v.iter()
+            .any(|e| matches!(e, EvalViolation::InvalidTransactionType))
+    );
 }
 
 #[tokio::test]
@@ -160,7 +169,9 @@ 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 +189,9 @@ 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());
 }
 
@@ -196,8 +209,13 @@ 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();
-    assert!(v.iter().any(|e| matches!(e, EvalViolation::InvalidTarget { .. })));
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
+        .await
+        .unwrap();
+    assert!(
+        v.iter()
+            .any(|e| matches!(e, EvalViolation::InvalidTarget { .. }))
+    );
 }
 
 #[tokio::test]
@@ -207,7 +225,9 @@ async fn evaluate_passes_volume_within_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();
 
     // Record a past transfer of 500 (within 1000 limit)
     use crate::db::{models::NewEvmTokenTransferLog, schema::evm_token_transfer_log};
@@ -224,12 +244,22 @@ async fn evaluate_passes_volume_within_limit() {
         .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();
-    assert!(!v.iter().any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded)));
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
+        .await
+        .unwrap();
+    assert!(
+        !v.iter()
+            .any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded))
+    );
 }
 
 #[tokio::test]
@@ -239,7 +269,9 @@ 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)
@@ -255,12 +287,22 @@ async fn evaluate_rejects_volume_over_limit() {
         .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();
-    assert!(v.iter().any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded)));
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
+        .await
+        .unwrap();
+    assert!(
+        v.iter()
+            .any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded))
+    );
 }
 
 #[tokio::test]
@@ -277,8 +319,13 @@ 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();
-    assert!(!v.iter().any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded)));
+    let v = TokenTransfer::evaluate(&context, &m, &grant, &mut *conn)
+        .await
+        .unwrap();
+    assert!(
+        !v.iter()
+            .any(|e| matches!(e, EvalViolation::VolumetricLimitExceeded))
+    );
 }
 
 // ── try_find_grant ───────────────────────────────────────────────────────
@@ -290,7 +337,9 @@ 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 +361,9 @@ 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 +379,9 @@ 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 +408,13 @@ 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 +427,17 @@ 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]
@@ -388,9 +450,13 @@ 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)
-        .await
-        .unwrap();
+    TokenTransfer::create_grant(
+        &b2,
+        &make_settings(Some(RECIPIENT), Some(2_000)),
+        &mut *conn,
+    )
+    .await
+    .unwrap();
 
     let all = TokenTransfer::find_all_grants(&mut *conn).await.unwrap();
     assert_eq!(all.len(), 2);

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 memsafe::MemSafe;
+use k256::ecdsa::{self, RecoveryId, SigningKey, signature::hazmat::PrehashSigner};
 
 /// 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 w = cell.write().expect("MemSafe write");
-            rng.fill_bytes(w.as_mut());
-        }
-        let reader = cell.read().expect("MemSafe read");
+        let mut cell = SafeCell::new_inline(|w: &mut [u8; 32]| {
+            rng.fill_bytes(w);
+        });
+
+        let reader = cell.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> {
-        let reader = cell.read().map_err(Error::other)?;
+    pub fn from_cell(mut cell: SafeCell<Vec<u8>>) -> Result<Self> {
+        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(
-        &self,
-        tx: &mut dyn SignableTransaction<Signature>,
-    ) -> Result<Signature> {
+    fn sign_tx_inner(&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 +1,137 @@
+use arbiter_proto::{
+    proto::client::{
+        ClientRequest, ClientResponse, VaultState as ProtoVaultState,
+        client_request::Payload as ClientRequestPayload,
+        client_response::Payload as ClientResponsePayload,
+    },
+    transport::{Receiver, Sender, grpc::GrpcBi},
+};
+use kameo::{
+    actor::{ActorRef, Spawn as _},
+    error::SendError,
+};
+use tonic::Status;
+use tracing::{info, warn};
+
+use crate::{
+    actors::{
+        client::{
+            self, ClientConnection,
+            session::{ClientSession, Error, HandleQueryVaultState},
+        },
+        keyholder::KeyHolderState,
+    },
+    grpc::request_tracker::RequestTracker,
+    utils::defer,
+};
+
+mod auth;
+
+async fn dispatch_loop(
+    mut bi: GrpcBi<ClientRequest, ClientResponse>,
+    actor: ActorRef<ClientSession>,
+    mut request_tracker: RequestTracker,
+) {
+    loop {
+        let Some(conn) = bi.recv().await else {
+            return;
+        };
+
+        if dispatch_conn_message(&mut bi, &actor, &mut request_tracker, conn)
+            .await
+            .is_err()
+        {
+            return;
+        }
+    }
+}
+
+async fn dispatch_conn_message(
+    bi: &mut GrpcBi<ClientRequest, ClientResponse>,
+    actor: &ActorRef<ClientSession>,
+    request_tracker: &mut RequestTracker,
+    conn: Result<ClientRequest, Status>,
+) -> Result<(), ()> {
+    let conn = match conn {
+        Ok(conn) => conn,
+        Err(err) => {
+            warn!(error = ?err, "Failed to receive client request");
+            return Err(());
+        }
+    };
+
+    let request_id = match request_tracker.request(conn.request_id) {
+        Ok(request_id) => request_id,
+        Err(err) => {
+            let _ = bi.send(Err(err)).await;
+            return Err(());
+        }
+    };
+    let Some(payload) = conn.payload else {
+        let _ = bi
+            .send(Err(Status::invalid_argument(
+                "Missing client request payload",
+            )))
+            .await;
+        return Err(());
+    };
+
+    let payload = match payload {
+        ClientRequestPayload::QueryVaultState(_) => ClientResponsePayload::VaultState(
+            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
+                }
+            }
+            .into(),
+        ),
+        payload => {
+            warn!(?payload, "Unsupported post-auth client request");
+            let _ = bi
+                .send(Err(Status::invalid_argument("Unsupported client request")))
+                .await;
+            return Err(());
+        }
+    };
+
+    bi.send(Ok(ClientResponse {
+        request_id: Some(request_id),
+        payload: Some(payload),
+    }))
+    .await
+    .map_err(|_| ())
+}
+
+pub async fn start(conn: ClientConnection, mut bi: GrpcBi<ClientRequest, ClientResponse>) {
+    let mut conn = conn;
+    let mut request_tracker = RequestTracker::default();
+    let mut response_id = None;
+
+    match auth::start(&mut conn, &mut bi, &mut request_tracker, &mut response_id).await {
+        Ok(_) => {
+            let actor =
+                client::session::ClientSession::spawn(client::session::ClientSession::new(conn));
+            let actor_for_cleanup = actor.clone();
+            let _ = defer(move || {
+                actor_for_cleanup.kill();
+            });
+
+            info!("Client authenticated successfully");
+            dispatch_loop(bi, actor, request_tracker).await;
+        }
+        Err(e) => {
+            let mut transport = auth::AuthTransportAdapter::new(
+                &mut bi,
+                &mut request_tracker,
+                &mut response_id,
+            );
+            let _ = transport.send(Err(e.clone())).await;
+            warn!(error = ?e, "Authentication failed");
+        }
+    }
+}

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

@@ -0,0 +1,173 @@
+use arbiter_proto::{
+    proto::client::{
+        AuthChallenge as ProtoAuthChallenge, AuthChallengeRequest as ProtoAuthChallengeRequest,
+        AuthChallengeSolution as ProtoAuthChallengeSolution, AuthResult as ProtoAuthResult,
+        ClientRequest, ClientResponse, client_request::Payload as ClientRequestPayload,
+        client_response::Payload as ClientResponsePayload,
+    },
+    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,
+    response_id: &'a mut Option<i32>,
+}
+
+impl<'a> AuthTransportAdapter<'a> {
+    pub fn new(
+        bi: &'a mut GrpcBi<ClientRequest, ClientResponse>,
+        request_tracker: &'a mut RequestTracker,
+        response_id: &'a mut Option<i32>,
+    ) -> Self {
+        Self {
+            bi,
+            request_tracker,
+            response_id,
+        }
+    }
+
+    fn response_to_proto(response: auth::Outbound) -> ClientResponsePayload {
+        match response {
+            auth::Outbound::AuthChallenge { pubkey, nonce } => {
+                ClientResponsePayload::AuthChallenge(ProtoAuthChallenge {
+                    pubkey: pubkey.to_bytes().to_vec(),
+                    nonce,
+                })
+            }
+            auth::Outbound::AuthSuccess => {
+                ClientResponsePayload::AuthResult(ProtoAuthResult::Success.into())
+            }
+        }
+    }
+
+    fn error_to_proto(error: auth::Error) -> ClientResponsePayload {
+        ClientResponsePayload::AuthResult(
+            match error {
+                auth::Error::InvalidChallengeSolution => ProtoAuthResult::InvalidSignature,
+                auth::Error::ApproveError(auth::ApproveError::Denied) => {
+                    ProtoAuthResult::ApprovalDenied
+                }
+                auth::Error::ApproveError(auth::ApproveError::Upstream(
+                    crate::actors::router::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: ClientResponsePayload,
+    ) -> Result<(), TransportError> {
+        let request_id = self.response_id.take();
+
+        self.bi
+            .send(Ok(ClientResponse {
+                request_id,
+                payload: Some(payload),
+            }))
+            .await
+    }
+
+    async fn send_auth_result(&mut self, result: ProtoAuthResult) -> Result<(), TransportError> {
+        self.send_client_response(ClientResponsePayload::AuthResult(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;
+            }
+        };
+
+        let request_id = match self.request_tracker.request(request.request_id) {
+            Ok(request_id) => request_id,
+            Err(error) => {
+                let _ = self.bi.send(Err(error)).await;
+                return None;
+            }
+        };
+        *self.response_id = Some(request_id);
+
+        let payload = request.payload?;
+
+        match payload {
+            ClientRequestPayload::AuthChallengeRequest(ProtoAuthChallengeRequest { pubkey }) => {
+                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 })
+            }
+            ClientRequestPayload::AuthChallengeSolution(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 })
+            }
+            _ => {
+                let _ = self
+                    .bi
+                    .send(Err(Status::invalid_argument("Unsupported client auth request")))
+                    .await;
+                None
+            }
+        }
+    }
+}
+
+impl Bi<auth::Inbound, Result<auth::Outbound, auth::Error>> for AuthTransportAdapter<'_> {}
+
+pub async fn start(
+    conn: &mut ClientConnection,
+    bi: &mut GrpcBi<ClientRequest, ClientResponse>,
+    request_tracker: &mut RequestTracker,
+    response_id: &mut Option<i32>,
+) -> Result<(), auth::Error> {
+    let mut transport = AuthTransportAdapter::new(bi, request_tracker, response_id);
+    client::auth::authenticate(conn, &mut transport).await?;
+    Ok(())
+}

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

@@ -0,0 +1,62 @@
+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,
+};
+
+pub mod client;
+mod request_tracker;
+pub mod user_agent;
+
+#[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 +1,20 @@
+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)
+    }
+}

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

@@ -0,0 +1,604 @@
+use tokio::sync::mpsc;
+
+use arbiter_proto::{
+    google::protobuf::{Empty as ProtoEmpty, Timestamp as ProtoTimestamp},
+    proto::{
+        evm::{
+            EtherTransferSettings as ProtoEtherTransferSettings, EvmError as ProtoEvmError,
+            EvmGrantCreateRequest, EvmGrantCreateResponse, EvmGrantDeleteRequest,
+            EvmGrantDeleteResponse, EvmGrantList, EvmGrantListResponse, GrantEntry,
+            SharedSettings as ProtoSharedSettings, SpecificGrant as ProtoSpecificGrant,
+            TokenTransferSettings as ProtoTokenTransferSettings,
+            TransactionRateLimit as ProtoTransactionRateLimit,
+            VolumeRateLimit as ProtoVolumeRateLimit, 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,
+            specific_grant::Grant as ProtoSpecificGrantType,
+            wallet_create_response::Result as WalletCreateResult,
+            wallet_list_response::Result as WalletListResult,
+        },
+        user_agent::{
+            BootstrapEncryptedKey as ProtoBootstrapEncryptedKey,
+            BootstrapResult as ProtoBootstrapResult,
+            SdkClientConnectionResponse as ProtoSdkClientConnectionResponse,
+            UnsealEncryptedKey as ProtoUnsealEncryptedKey, UnsealResult as ProtoUnsealResult,
+            UnsealStart, UserAgentRequest, UserAgentResponse, VaultState as ProtoVaultState,
+            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 chrono::{TimeZone, Utc};
+use kameo::{
+    actor::{ActorRef, Spawn as _},
+    error::SendError,
+};
+use tonic::Status;
+use tracing::{info, warn};
+
+use crate::{
+    actors::{
+        keyholder::KeyHolderState,
+        user_agent::{
+            OutOfBand, UserAgentConnection, UserAgentSession,
+            session::{
+                BootstrapError, Error, HandleBootstrapEncryptedKey, HandleEvmWalletCreate,
+                HandleEvmWalletList, HandleGrantCreate, HandleGrantDelete, HandleGrantList,
+                HandleQueryVaultState, HandleUnsealEncryptedKey, HandleUnsealRequest, UnsealError,
+            },
+        },
+    },
+    evm::policies::{
+        Grant, SharedGrantSettings, SpecificGrant, TransactionRateLimit, VolumeRateLimit,
+        ether_transfer, token_transfers,
+    },
+    grpc::request_tracker::RequestTracker,
+    utils::defer,
+};
+use alloy::primitives::{Address, U256};
+mod auth;
+
+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 {
+                    return;
+                };
+
+                if send_out_of_band(&mut bi, oob).await.is_err() {
+                    return;
+                }
+            }
+
+            conn = bi.recv() => {
+                let Some(conn) = conn else {
+                    return;
+                };
+
+                if dispatch_conn_message(&mut bi, &actor, &mut request_tracker, conn)
+                    .await
+                    .is_err()
+                {
+                    return;
+                }
+            }
+        }
+    }
+}
+
+async fn dispatch_conn_message(
+    bi: &mut GrpcBi<UserAgentRequest, UserAgentResponse>,
+    actor: &ActorRef<UserAgentSession>,
+    request_tracker: &mut RequestTracker,
+    conn: Result<UserAgentRequest, Status>,
+) -> Result<(), ()> {
+    let conn = match conn {
+        Ok(conn) => conn,
+        Err(err) => {
+            warn!(error = ?err, "Failed to receive user agent request");
+            return Err(());
+        }
+    };
+
+    let request_id = match request_tracker.request(conn.id) {
+        Ok(request_id) => request_id,
+        Err(err) => {
+            let _ = bi.send(Err(err)).await;
+            return Err(());
+        }
+    };
+
+    let Some(payload) = conn.payload else {
+        let _ = bi
+            .send(Err(Status::invalid_argument(
+                "Missing user-agent request payload",
+            )))
+            .await;
+        return Err(());
+    };
+
+    let payload = match payload {
+        UserAgentRequestPayload::UnsealStart(UnsealStart { client_pubkey }) => {
+            let client_pubkey = match <[u8; 32]>::try_from(client_pubkey) {
+                Ok(bytes) => x25519_dalek::PublicKey::from(bytes),
+                Err(_) => {
+                    let _ = bi
+                        .send(Err(Status::invalid_argument("Invalid X25519 public key")))
+                        .await;
+                    return Err(());
+                }
+            };
+
+            match actor.ask(HandleUnsealRequest { client_pubkey }).await {
+                Ok(response) => UserAgentResponsePayload::UnsealStartResponse(
+                    arbiter_proto::proto::user_agent::UnsealStartResponse {
+                        server_pubkey: response.server_pubkey.as_bytes().to_vec(),
+                    },
+                ),
+                Err(err) => {
+                    warn!(error = ?err, "Failed to handle unseal start request");
+                    let _ = bi
+                        .send(Err(Status::internal("Failed to start unseal flow")))
+                        .await;
+                    return Err(());
+                }
+            }
+        }
+        UserAgentRequestPayload::UnsealEncryptedKey(ProtoUnsealEncryptedKey {
+            nonce,
+            ciphertext,
+            associated_data,
+        }) => UserAgentResponsePayload::UnsealResult(
+            match actor
+                .ask(HandleUnsealEncryptedKey {
+                    nonce,
+                    ciphertext,
+                    associated_data,
+                })
+                .await
+            {
+                Ok(()) => ProtoUnsealResult::Success,
+                Err(SendError::HandlerError(UnsealError::InvalidKey)) => {
+                    ProtoUnsealResult::InvalidKey
+                }
+                Err(err) => {
+                    warn!(error = ?err, "Failed to handle unseal request");
+                    let _ = bi
+                        .send(Err(Status::internal("Failed to unseal vault")))
+                        .await;
+                    return Err(());
+                }
+            }
+            .into(),
+        ),
+        UserAgentRequestPayload::BootstrapEncryptedKey(ProtoBootstrapEncryptedKey {
+            nonce,
+            ciphertext,
+            associated_data,
+        }) => UserAgentResponsePayload::BootstrapResult(
+            match actor
+                .ask(HandleBootstrapEncryptedKey {
+                    nonce,
+                    ciphertext,
+                    associated_data,
+                })
+                .await
+            {
+                Ok(()) => ProtoBootstrapResult::Success,
+                Err(SendError::HandlerError(BootstrapError::InvalidKey)) => {
+                    ProtoBootstrapResult::InvalidKey
+                }
+                Err(SendError::HandlerError(BootstrapError::AlreadyBootstrapped)) => {
+                    ProtoBootstrapResult::AlreadyBootstrapped
+                }
+                Err(err) => {
+                    warn!(error = ?err, "Failed to handle bootstrap request");
+                    let _ = bi
+                        .send(Err(Status::internal("Failed to bootstrap vault")))
+                        .await;
+                    return Err(());
+                }
+            }
+            .into(),
+        ),
+        UserAgentRequestPayload::QueryVaultState(_) => UserAgentResponsePayload::VaultState(
+            match actor.ask(HandleQueryVaultState {}).await {
+                Ok(KeyHolderState::Unbootstrapped) => ProtoVaultState::Unbootstrapped,
+                Ok(KeyHolderState::Sealed) => ProtoVaultState::Sealed,
+                Ok(KeyHolderState::Unsealed) => ProtoVaultState::Unsealed,
+                Err(err) => {
+                    warn!(error = ?err, "Failed to query vault state");
+                    ProtoVaultState::Error
+                }
+            }
+            .into(),
+        ),
+        UserAgentRequestPayload::EvmWalletCreate(_) => UserAgentResponsePayload::EvmWalletCreate(
+            EvmGrantOrWallet::wallet_create_response(actor.ask(HandleEvmWalletCreate {}).await),
+        ),
+        UserAgentRequestPayload::EvmWalletList(_) => UserAgentResponsePayload::EvmWalletList(
+            EvmGrantOrWallet::wallet_list_response(actor.ask(HandleEvmWalletList {}).await),
+        ),
+        UserAgentRequestPayload::EvmGrantList(_) => UserAgentResponsePayload::EvmGrantList(
+            EvmGrantOrWallet::grant_list_response(actor.ask(HandleGrantList {}).await),
+        ),
+        UserAgentRequestPayload::EvmGrantCreate(EvmGrantCreateRequest {
+            client_id,
+            shared,
+            specific,
+        }) => {
+            let (basic, grant) = match parse_grant_request(shared, specific) {
+                Ok(values) => values,
+                Err(status) => {
+                    let _ = bi.send(Err(status)).await;
+                    return Err(());
+                }
+            };
+
+            UserAgentResponsePayload::EvmGrantCreate(EvmGrantOrWallet::grant_create_response(
+                actor
+                    .ask(HandleGrantCreate {
+                        client_id,
+                        basic,
+                        grant,
+                    })
+                    .await,
+            ))
+        }
+        UserAgentRequestPayload::EvmGrantDelete(EvmGrantDeleteRequest { grant_id }) => {
+            UserAgentResponsePayload::EvmGrantDelete(EvmGrantOrWallet::grant_delete_response(
+                actor.ask(HandleGrantDelete { grant_id }).await,
+            ))
+        }
+        payload => {
+            warn!(?payload, "Unsupported post-auth user agent request");
+            let _ = bi
+                .send(Err(Status::invalid_argument(
+                    "Unsupported user-agent request",
+                )))
+                .await;
+            return Err(());
+        }
+    };
+
+    bi.send(Ok(UserAgentResponse {
+        id: Some(request_id),
+        payload: Some(payload),
+    }))
+    .await
+    .map_err(|_| ())
+}
+
+async fn send_out_of_band(
+    bi: &mut GrpcBi<UserAgentRequest, UserAgentResponse>,
+    oob: OutOfBand,
+) -> Result<(), ()> {
+    let payload = match oob {
+        // The current protobuf response payload carries only an approval boolean.
+        // Keep emitting this shape until a dedicated out-of-band request/cancel payload
+        // is reintroduced in the protocol definition.
+        OutOfBand::ClientConnectionRequest { pubkey: _ } => {
+            UserAgentResponsePayload::SdkClientConnectionResponse(
+                ProtoSdkClientConnectionResponse { approved: false },
+            )
+        }
+        OutOfBand::ClientConnectionCancel => UserAgentResponsePayload::SdkClientConnectionResponse(
+            ProtoSdkClientConnectionResponse { approved: false },
+        ),
+    };
+
+    bi.send(Ok(UserAgentResponse {
+        id: None,
+        payload: Some(payload),
+    }))
+    .await
+    .map_err(|_| ())
+}
+
+fn parse_grant_request(
+    shared: Option<ProtoSharedSettings>,
+    specific: Option<ProtoSpecificGrant>,
+) -> Result<(SharedGrantSettings, SpecificGrant), Status> {
+    let shared = shared.ok_or_else(|| Status::invalid_argument("Missing shared grant settings"))?;
+    let specific =
+        specific.ok_or_else(|| Status::invalid_argument("Missing specific grant settings"))?;
+
+    Ok((
+        shared_settings_from_proto(shared)?,
+        specific_grant_from_proto(specific)?,
+    ))
+}
+
+fn shared_settings_from_proto(shared: ProtoSharedSettings) -> Result<SharedGrantSettings, Status> {
+    Ok(SharedGrantSettings {
+        wallet_id: shared.wallet_id,
+        client_id: 0,
+        chain: shared.chain_id,
+        valid_from: shared.valid_from.map(proto_timestamp_to_utc).transpose()?,
+        valid_until: shared.valid_until.map(proto_timestamp_to_utc).transpose()?,
+        max_gas_fee_per_gas: shared
+            .max_gas_fee_per_gas
+            .as_deref()
+            .map(u256_from_proto_bytes)
+            .transpose()?,
+        max_priority_fee_per_gas: shared
+            .max_priority_fee_per_gas
+            .as_deref()
+            .map(u256_from_proto_bytes)
+            .transpose()?,
+        rate_limit: shared.rate_limit.map(|limit| TransactionRateLimit {
+            count: limit.count,
+            window: chrono::Duration::seconds(limit.window_secs),
+        }),
+    })
+}
+
+fn specific_grant_from_proto(specific: ProtoSpecificGrant) -> Result<SpecificGrant, Status> {
+    match specific.grant {
+        Some(ProtoSpecificGrantType::EtherTransfer(ProtoEtherTransferSettings {
+            targets,
+            limit,
+        })) => Ok(SpecificGrant::EtherTransfer(ether_transfer::Settings {
+            target: targets
+                .into_iter()
+                .map(address_from_bytes)
+                .collect::<Result<_, _>>()?,
+            limit: volume_rate_limit_from_proto(limit.ok_or_else(|| {
+                Status::invalid_argument("Missing ether transfer volume rate limit")
+            })?)?,
+        })),
+        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(volume_rate_limit_from_proto)
+                .collect::<Result<_, _>>()?,
+        })),
+        None => Err(Status::invalid_argument("Missing specific grant kind")),
+    }
+}
+
+fn volume_rate_limit_from_proto(limit: ProtoVolumeRateLimit) -> Result<VolumeRateLimit, Status> {
+    Ok(VolumeRateLimit {
+        max_volume: u256_from_proto_bytes(&limit.max_volume)?,
+        window: chrono::Duration::seconds(limit.window_secs),
+    })
+}
+
+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))
+}
+
+fn proto_timestamp_to_utc(timestamp: ProtoTimestamp) -> Result<chrono::DateTime<Utc>, Status> {
+    Utc.timestamp_opt(timestamp.seconds, timestamp.nanos as u32)
+        .single()
+        .ok_or_else(|| Status::invalid_argument("Invalid timestamp"))
+}
+
+fn shared_settings_to_proto(shared: SharedGrantSettings) -> ProtoSharedSettings {
+    ProtoSharedSettings {
+        wallet_id: shared.wallet_id,
+        chain_id: shared.chain,
+        valid_from: shared.valid_from.map(|time| ProtoTimestamp {
+            seconds: time.timestamp(),
+            nanos: time.timestamp_subsec_nanos() as i32,
+        }),
+        valid_until: shared.valid_until.map(|time| ProtoTimestamp {
+            seconds: time.timestamp(),
+            nanos: time.timestamp_subsec_nanos() as i32,
+        }),
+        max_gas_fee_per_gas: shared
+            .max_gas_fee_per_gas
+            .map(|value| value.to_be_bytes::<32>().to_vec()),
+        max_priority_fee_per_gas: shared
+            .max_priority_fee_per_gas
+            .map(|value| value.to_be_bytes::<32>().to_vec()),
+        rate_limit: shared.rate_limit.map(|limit| ProtoTransactionRateLimit {
+            count: limit.count,
+            window_secs: limit.window.num_seconds(),
+        }),
+    }
+}
+
+fn specific_grant_to_proto(grant: SpecificGrant) -> ProtoSpecificGrant {
+    let grant = match grant {
+        SpecificGrant::EtherTransfer(settings) => {
+            ProtoSpecificGrantType::EtherTransfer(ProtoEtherTransferSettings {
+                targets: settings
+                    .target
+                    .into_iter()
+                    .map(|address| address.to_vec())
+                    .collect(),
+                limit: Some(ProtoVolumeRateLimit {
+                    max_volume: settings.limit.max_volume.to_be_bytes::<32>().to_vec(),
+                    window_secs: settings.limit.window.num_seconds(),
+                }),
+            })
+        }
+        SpecificGrant::TokenTransfer(settings) => {
+            ProtoSpecificGrantType::TokenTransfer(ProtoTokenTransferSettings {
+                token_contract: settings.token_contract.to_vec(),
+                target: settings.target.map(|address| address.to_vec()),
+                volume_limits: settings
+                    .volume_limits
+                    .into_iter()
+                    .map(|limit| ProtoVolumeRateLimit {
+                        max_volume: limit.max_volume.to_be_bytes::<32>().to_vec(),
+                        window_secs: limit.window.num_seconds(),
+                    })
+                    .collect(),
+            })
+        }
+    };
+
+    ProtoSpecificGrant { grant: Some(grant) }
+}
+
+struct EvmGrantOrWallet;
+
+impl EvmGrantOrWallet {
+    fn wallet_create_response<M>(
+        result: Result<Address, SendError<M, Error>>,
+    ) -> WalletCreateResponse {
+        let result = match result {
+            Ok(wallet) => WalletCreateResult::Wallet(WalletEntry {
+                address: wallet.to_vec(),
+            }),
+            Err(err) => {
+                warn!(error = ?err, "Failed to create EVM wallet");
+                WalletCreateResult::Error(ProtoEvmError::Internal.into())
+            }
+        };
+
+        WalletCreateResponse {
+            result: Some(result),
+        }
+    }
+
+    fn wallet_list_response<M>(
+        result: Result<Vec<Address>, SendError<M, Error>>,
+    ) -> WalletListResponse {
+        let result = match result {
+            Ok(wallets) => WalletListResult::Wallets(WalletList {
+                wallets: wallets
+                    .into_iter()
+                    .map(|wallet| WalletEntry {
+                        address: wallet.to_vec(),
+                    })
+                    .collect(),
+            }),
+            Err(err) => {
+                warn!(error = ?err, "Failed to list EVM wallets");
+                WalletListResult::Error(ProtoEvmError::Internal.into())
+            }
+        };
+
+        WalletListResponse {
+            result: Some(result),
+        }
+    }
+
+    fn grant_create_response<M>(
+        result: Result<i32, SendError<M, Error>>,
+    ) -> EvmGrantCreateResponse {
+        let result = match result {
+            Ok(grant_id) => EvmGrantCreateResult::GrantId(grant_id),
+            Err(err) => {
+                warn!(error = ?err, "Failed to create EVM grant");
+                EvmGrantCreateResult::Error(ProtoEvmError::Internal.into())
+            }
+        };
+
+        EvmGrantCreateResponse {
+            result: Some(result),
+        }
+    }
+
+    fn grant_delete_response<M>(result: Result<(), SendError<M, Error>>) -> EvmGrantDeleteResponse {
+        let result = match result {
+            Ok(()) => EvmGrantDeleteResult::Ok(ProtoEmpty {}),
+            Err(err) => {
+                warn!(error = ?err, "Failed to delete EVM grant");
+                EvmGrantDeleteResult::Error(ProtoEvmError::Internal.into())
+            }
+        };
+
+        EvmGrantDeleteResponse {
+            result: Some(result),
+        }
+    }
+
+    fn grant_list_response<M>(
+        result: Result<Vec<Grant<SpecificGrant>>, SendError<M, Error>>,
+    ) -> EvmGrantListResponse {
+        let result = match result {
+            Ok(grants) => EvmGrantListResult::Grants(EvmGrantList {
+                grants: grants
+                    .into_iter()
+                    .map(|grant| GrantEntry {
+                        id: grant.id,
+                        client_id: grant.shared.client_id,
+                        shared: Some(shared_settings_to_proto(grant.shared)),
+                        specific: Some(specific_grant_to_proto(grant.settings)),
+                    })
+                    .collect(),
+            }),
+            Err(err) => {
+                warn!(error = ?err, "Failed to list EVM grants");
+                EvmGrantListResult::Error(ProtoEvmError::Internal.into())
+            }
+        };
+
+        EvmGrantListResponse {
+            result: Some(result),
+        }
+    }
+}
+
+pub async fn start(
+    mut conn: UserAgentConnection,
+    mut bi: GrpcBi<UserAgentRequest, UserAgentResponse>,
+) {
+    let mut request_tracker = RequestTracker::default();
+    let mut response_id = None;
+
+    let pubkey = match auth::start(&mut conn, &mut bi, &mut request_tracker, &mut response_id).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();
+
+    let _ = defer(move || {
+        actor_for_cleanup.kill();
+    });
+
+    info!(?pubkey, "User authenticated successfully");
+    dispatch_loop(bi, actor, oob_receiver, request_tracker).await;
+}

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

@@ -0,0 +1,180 @@
+use arbiter_proto::{
+    proto::user_agent::{
+        AuthChallenge as ProtoAuthChallenge, AuthChallengeRequest as ProtoAuthChallengeRequest,
+        AuthChallengeSolution as ProtoAuthChallengeSolution, AuthResult as ProtoAuthResult,
+        KeyType as ProtoKeyType, UserAgentRequest, UserAgentResponse,
+        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,
+    response_id: &'a mut Option<i32>,
+}
+
+impl<'a> AuthTransportAdapter<'a> {
+    pub fn new(
+        bi: &'a mut GrpcBi<UserAgentRequest, UserAgentResponse>,
+        request_tracker: &'a mut RequestTracker,
+        response_id: &'a mut Option<i32>,
+    ) -> Self {
+        Self {
+            bi,
+            request_tracker,
+            response_id,
+        }
+    }
+
+    async fn send_user_agent_response(
+        &mut self,
+        payload: UserAgentResponsePayload,
+    ) -> Result<(), TransportError> {
+        let id = self.response_id.take();
+
+        self.bi
+            .send(Ok(UserAgentResponse {
+                id,
+                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 }) => {
+                UserAgentResponsePayload::AuthChallenge(ProtoAuthChallenge { nonce })
+            }
+            Ok(Outbound::AuthSuccess) => {
+                UserAgentResponsePayload::AuthResult(ProtoAuthResult::Success.into())
+            }
+            Err(Error::UnregisteredPublicKey) => {
+                UserAgentResponsePayload::AuthResult(ProtoAuthResult::InvalidKey.into())
+            }
+            Err(Error::InvalidChallengeSolution) => {
+                UserAgentResponsePayload::AuthResult(ProtoAuthResult::InvalidSignature.into())
+            }
+            Err(Error::InvalidBootstrapToken) => {
+                UserAgentResponsePayload::AuthResult(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;
+            }
+        };
+
+        let request_id = match self.request_tracker.request(request.id) {
+            Ok(request_id) => request_id,
+            Err(error) => {
+                let _ = self.bi.send(Err(error)).await;
+                return None;
+            }
+        };
+        *self.response_id = Some(request_id);
+
+        let Some(payload) = request.payload else {
+            warn!(
+                event = "received request with empty payload",
+                "grpc.useragent.auth_adapter"
+            );
+            return None;
+        };
+
+        match payload {
+            UserAgentRequestPayload::AuthChallengeRequest(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,
+                })
+            }
+            UserAgentRequestPayload::AuthChallengeSolution(ProtoAuthChallengeSolution {
+                signature,
+            }) => Some(auth::Inbound::AuthChallengeSolution { signature }),
+            _ => {
+                let _ = self
+                    .bi
+                    .send(Err(Status::invalid_argument(
+                        "Unsupported user-agent auth request",
+                    )))
+                    .await;
+                None
+            }
+        }
+    }
+}
+
+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,
+    response_id: &mut Option<i32>,
+) -> Result<AuthPublicKey, auth::Error> {
+    let transport = AuthTransportAdapter::new(bi, request_tracker, response_id);
+    auth::authenticate(conn, transport).await
+}

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

@@ -1,136 +1,13 @@
 #![forbid(unsafe_code)]
-use arbiter_proto::{
-    proto::{
-        client::{ClientRequest, ClientResponse},
-        user_agent::{UserAgentRequest, UserAgentResponse},
-    },
-    transport::{IdentityRecvConverter, SendConverter, grpc},
-};
-use async_trait::async_trait;
-use tokio_stream::wrappers::ReceiverStream;
-
-use tokio::sync::mpsc;
-use tonic::{Request, Response, Status};
-use tracing::info;
-
-use crate::{
-    actors::{
-        client::{self, ClientConnection as ClientConnectionProps, ClientError, connect_client},
-        user_agent::{self, TransportResponseError, UserAgentConnection, connect_user_agent},
-    },
-    context::ServerContext,
-};
+use crate::context::ServerContext;
 
 pub mod actors;
 pub mod context;
 pub mod db;
 pub mod evm;
-
-const DEFAULT_CHANNEL_SIZE: usize = 1000;
-
-struct UserAgentGrpcSender;
-
-impl SendConverter for UserAgentGrpcSender {
-    type Input = Result<UserAgentResponse, TransportResponseError>;
-    type Output = Result<UserAgentResponse, Status>;
-
-    fn convert(&self, item: Self::Input) -> Self::Output {
-        match item {
-            Ok(message) => Ok(message),
-            Err(err) => Err(user_agent_error_status(err)),
-        }
-    }
-}
-
-struct ClientGrpcSender;
-
-impl SendConverter for ClientGrpcSender {
-    type Input = Result<ClientResponse, ClientError>;
-    type Output = Result<ClientResponse, Status>;
-
-    fn convert(&self, item: Self::Input) -> Self::Output {
-        match item {
-            Ok(message) => Ok(message),
-            Err(err) => Err(client_error_status(err)),
-        }
-    }
-}
-
-fn client_error_status(value: ClientError) -> Status {
-    match value {
-        ClientError::MissingRequestPayload | ClientError::UnexpectedRequestPayload => {
-            Status::invalid_argument("Expected message with payload")
-        }
-        ClientError::StateTransitionFailed => Status::internal("State machine error"),
-        ClientError::Auth(ref err) => client_auth_error_status(err),
-        ClientError::ConnectionRegistrationFailed => {
-            Status::internal("Connection registration failed")
-        }
-    }
-}
-
-fn client_auth_error_status(value: &client::auth::Error) -> Status {
-    use client::auth::Error;
-    match value {
-        Error::UnexpectedMessagePayload | Error::InvalidClientPubkeyLength => {
-            Status::invalid_argument(value.to_string())
-        }
-        Error::InvalidAuthPubkeyEncoding => {
-            Status::invalid_argument("Failed to convert pubkey to VerifyingKey")
-        }
-        Error::InvalidChallengeSolution => Status::unauthenticated(value.to_string()),
-        Error::NotRegistered => Status::permission_denied(value.to_string()),
-        Error::Transport => Status::internal("Transport error"),
-        Error::DatabasePoolUnavailable => Status::internal("Database pool error"),
-        Error::DatabaseOperationFailed => Status::internal("Database error"),
-        Error::InternalError => Status::internal("Internal error"),
-    }
-}
-
-fn user_agent_error_status(value: TransportResponseError) -> Status {
-    match value {
-        TransportResponseError::MissingRequestPayload
-        | TransportResponseError::UnexpectedRequestPayload => {
-            Status::invalid_argument("Expected message with payload")
-        }
-        TransportResponseError::InvalidStateForUnsealEncryptedKey => {
-            Status::failed_precondition("Invalid state for unseal encrypted key")
-        }
-        TransportResponseError::InvalidClientPubkeyLength => {
-            Status::invalid_argument("client_pubkey must be 32 bytes")
-        }
-        TransportResponseError::StateTransitionFailed => Status::internal("State machine error"),
-        TransportResponseError::KeyHolderActorUnreachable => {
-            Status::internal("Vault is not available")
-        }
-        TransportResponseError::Auth(ref err) => auth_error_status(err),
-        TransportResponseError::ConnectionRegistrationFailed => {
-            Status::internal("Failed registering connection")
-        }
-    }
-}
-
-fn auth_error_status(value: &user_agent::auth::Error) -> Status {
-    use user_agent::auth::Error;
-    match value {
-        Error::UnexpectedMessagePayload | Error::InvalidClientPubkeyLength => {
-            Status::invalid_argument(value.to_string())
-        }
-        Error::InvalidAuthPubkeyEncoding => {
-            Status::invalid_argument("Failed to convert pubkey to VerifyingKey")
-        }
-        Error::PublicKeyNotRegistered | Error::InvalidChallengeSolution => {
-            Status::unauthenticated(value.to_string())
-        }
-        Error::InvalidBootstrapToken => Status::invalid_argument("Invalid bootstrap token"),
-        Error::Transport => Status::internal("Transport error"),
-        Error::BootstrapperActorUnreachable => {
-            Status::internal("Bootstrap token consumption failed")
-        }
-        Error::DatabasePoolUnavailable => Status::internal("Database pool error"),
-        Error::DatabaseOperationFailed => Status::internal("Database error"),
-    }
-}
+pub mod grpc;
+pub mod safe_cell;
+pub mod utils;
 
 pub struct Server {
     context: ServerContext,
@@ -141,61 +18,3 @@ impl Server {
         Self { context }
     }
 }
-
-#[async_trait]
-impl arbiter_proto::proto::arbiter_service_server::ArbiterService for 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 (tx, rx) = mpsc::channel(DEFAULT_CHANNEL_SIZE);
-
-        let transport = grpc::GrpcAdapter::new(
-            tx,
-            req_stream,
-            IdentityRecvConverter::<ClientRequest>::new(),
-            ClientGrpcSender,
-        );
-        let props = ClientConnectionProps::new(
-            self.context.db.clone(),
-            Box::new(transport),
-            self.context.actors.clone(),
-        );
-        tokio::spawn(connect_client(props));
-
-        info!(event = "connection established", "grpc.client");
-
-        Ok(Response::new(ReceiverStream::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 (tx, rx) = mpsc::channel(DEFAULT_CHANNEL_SIZE);
-
-        let transport = grpc::GrpcAdapter::new(
-            tx,
-            req_stream,
-            IdentityRecvConverter::<UserAgentRequest>::new(),
-            UserAgentGrpcSender,
-        );
-        let props = UserAgentConnection::new(
-            self.context.db.clone(),
-            self.context.actors.clone(),
-            Box::new(transport),
-        );
-        tokio::spawn(connect_user_agent(props));
-
-        info!(event = "connection established", "grpc.user_agent");
-
-        Ok(Response::new(ReceiverStream::new(rx)))
-    }
-}

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

@@ -3,6 +3,7 @@ use std::net::SocketAddr;
 use arbiter_proto::{proto::arbiter_service_server::ArbiterServiceServer, url::ArbiterUrl};
 use arbiter_server::{Server, actors::bootstrap::GetToken, context::ServerContext, db};
 use miette::miette;
+use rustls::crypto::aws_lc_rs;
 use tonic::transport::{Identity, ServerTlsConfig};
 use tracing::info;
 
@@ -10,6 +11,8 @@ const PORT: u16 = 50051;
 
 #[tokio::main]
 async fn main() -> miette::Result<()> {
+    aws_lc_rs::default_provider().install_default().unwrap();
+
     tracing_subscriber::fmt()
         .with_env_filter(
             tracing_subscriber::EnvFilter::try_from_default_env()

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

@@ -0,0 +1,111 @@
+use std::ops::{Deref, DerefMut};
+use std::{any::type_name, fmt};
+
+use memsafe::MemSafe;
+
+pub trait SafeCellHandle<T> {
+    type CellRead<'a>: Deref<Target = T>
+    where
+        Self: 'a,
+        T: 'a;
+    type CellWrite<'a>: Deref<Target = T> + DerefMut<Target = T>
+    where
+        Self: 'a,
+        T: 'a;
+
+    fn new(value: T) -> Self
+    where
+        Self: Sized;
+
+    fn read(&mut self) -> Self::CellRead<'_>;
+    fn write(&mut self) -> Self::CellWrite<'_>;
+
+    fn new_inline<F>(f: F) -> Self
+    where
+        Self: Sized,
+        T: Default,
+        F: for<'a> FnOnce(&'a mut T),
+    {
+        let mut cell = Self::new(T::default());
+        {
+            let mut handle = cell.write();
+            f(handle.deref_mut());
+        }
+        cell
+    }
+
+    #[inline(always)]
+    fn read_inline<F, R>(&mut self, f: F) -> R
+    where
+        F: FnOnce(&T) -> R,
+    {
+        f(&*self.read())
+    }
+
+    #[inline(always)]
+    fn write_inline<F, R>(&mut self, f: F) -> R
+    where
+        F: FnOnce(&mut T) -> R,
+    {
+        f(&mut *self.write())
+    }
+}
+
+pub struct MemSafeCell<T>(MemSafe<T>);
+
+impl<T> fmt::Debug for MemSafeCell<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("MemSafeCell")
+            .field("inner", &format_args!("<protected {}>", type_name::<T>()))
+            .finish()
+    }
+}
+
+impl<T> SafeCellHandle<T> for MemSafeCell<T> {
+    type CellRead<'a>
+        = memsafe::MemSafeRead<'a, T>
+    where
+        Self: 'a,
+        T: 'a;
+    type CellWrite<'a>
+        = memsafe::MemSafeWrite<'a, T>
+    where
+        Self: 'a,
+        T: 'a;
+
+    fn new(value: T) -> Self {
+        match MemSafe::new(value) {
+            Ok(inner) => Self(inner),
+            Err(err) => {
+                // If protected memory cannot be allocated, process integrity is compromised.
+                abort_memory_breach("safe cell allocation", &err)
+            }
+        }
+    }
+
+    #[inline(always)]
+    fn read(&mut self) -> Self::CellRead<'_> {
+        match self.0.read() {
+            Ok(inner) => inner,
+            Err(err) => abort_memory_breach("safe cell read", &err),
+        }
+    }
+
+    #[inline(always)]
+    fn write(&mut self) -> Self::CellWrite<'_> {
+        match self.0.write() {
+            Ok(inner) => inner,
+            Err(err) => {
+                // If protected memory becomes unwritable here, treat it as a fatal memory breach.
+                abort_memory_breach("safe cell write", &err)
+            }
+        }
+    }
+}
+
+fn abort_memory_breach(action: &str, err: &memsafe::error::MemoryError) -> ! {
+    eprintln!("fatal {action}: {err}");
+    std::process::abort();
+}
+
+pub type SafeCell<T> = MemSafeCell<T>;

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

@@ -0,0 +1,16 @@
+struct DeferClosure<F: FnOnce()> {
+    f: Option<F>,
+}
+
+impl<F: FnOnce()> Drop for DeferClosure<F> {
+    fn drop(&mut self) {
+        if let Some(f) = self.f.take() {
+            f();
+        }
+    }
+}
+
+// Run some code when a scope is exited, similar to Go's defer statement
+pub fn defer<F: FnOnce()>(f: F) -> impl Drop + Sized {
+    DeferClosure { f: Some(f) }
+}

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

@@ -1,20 +1,7 @@
-use alloy::{
-    consensus::TxEip1559,
-    primitives::{Address, Bytes, TxKind, U256},
-    rlp::Encodable,
-};
-use arbiter_proto::proto::{
-    client::{
-        AuthChallengeRequest, AuthChallengeSolution, ClientRequest,
-        client_request::Payload as ClientRequestPayload,
-        client_response::Payload as ClientResponsePayload,
-    },
-    evm::EvmSignTransactionRequest,
-};
-use arbiter_proto::transport::Bi;
+use arbiter_proto::transport::{Receiver, Sender};
 use arbiter_server::actors::GlobalActors;
 use arbiter_server::{
-    actors::client::{ClientConnection, connect_client},
+    actors::client::{ClientConnection, auth, connect_client},
     db::{self, schema},
 };
 use diesel::{ExpressionMethods as _, insert_into};
@@ -30,19 +17,17 @@ pub async fn test_unregistered_pubkey_rejected() {
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-    let props = ClientConnection::new(db.clone(), Box::new(server_transport), actors);
-    let task = tokio::spawn(connect_client(props));
+    let props = ClientConnection::new(db.clone(), actors);
+    let task = tokio::spawn(async move {
+        let mut server_transport = server_transport;
+        connect_client(props, &mut server_transport).await;
+    });
 
     let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
 
     test_transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeRequest(
-                AuthChallengeRequest {
-                    pubkey: pubkey_bytes,
-                },
-            )),
+        .send(auth::Inbound::AuthChallengeRequest {
+            pubkey: new_key.verifying_key(),
         })
         .await
         .unwrap();
@@ -71,17 +56,16 @@ pub async fn test_challenge_auth() {
     let (server_transport, mut test_transport) = ChannelTransport::new();
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
-    let props = ClientConnection::new(db.clone(), Box::new(server_transport), actors);
-    let task = tokio::spawn(connect_client(props));
+    let props = ClientConnection::new(db.clone(), actors);
+    let task = tokio::spawn(async move {
+        let mut server_transport = server_transport;
+        connect_client(props, &mut server_transport).await;
+    });
 
     // Send challenge request
     test_transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeRequest(
-                AuthChallengeRequest {
-                    pubkey: pubkey_bytes,
-                },
-            )),
+        .send(auth::Inbound::AuthChallengeRequest {
+            pubkey: new_key.verifying_key(),
         })
         .await
         .unwrap();
@@ -92,131 +76,33 @@ pub async fn test_challenge_auth() {
         .await
         .expect("should receive challenge");
     let challenge = match response {
-        Ok(resp) => match resp.payload {
-            Some(ClientResponsePayload::AuthChallenge(c)) => c,
+        Ok(resp) => match resp {
+            auth::Outbound::AuthChallenge { pubkey, nonce } => (pubkey, nonce),
             other => panic!("Expected AuthChallenge, got {other:?}"),
         },
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
     // Sign the challenge and send solution
-    let formatted_challenge = arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
+    let formatted_challenge = arbiter_proto::format_challenge(challenge.1, challenge.0.as_bytes());
     let signature = new_key.sign(&formatted_challenge);
 
     test_transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeSolution(
-                AuthChallengeSolution {
-                    signature: signature.to_bytes().to_vec(),
-                },
-            )),
-        })
+        .send(auth::Inbound::AuthChallengeSolution { signature })
         .await
         .unwrap();
 
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive auth success");
+    match response {
+        Ok(auth::Outbound::AuthSuccess) => {}
+        Ok(other) => panic!("Expected AuthSuccess, got {other:?}"),
+        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
+    }
+
     // Auth completes, session spawned
     task.await.unwrap();
 }
 
-#[tokio::test]
-#[test_log::test]
-pub async fn test_evm_sign_request_payload_is_handled() {
-    let db = db::create_test_pool().await;
-
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
-
-    {
-        let mut conn = db.get().await.unwrap();
-        insert_into(schema::program_client::table)
-            .values(schema::program_client::public_key.eq(pubkey_bytes.clone()))
-            .execute(&mut conn)
-            .await
-            .unwrap();
-    }
-
-    let (server_transport, mut test_transport) = ChannelTransport::new();
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-
-    let props = ClientConnection::new(db.clone(), Box::new(server_transport), actors);
-    let task = tokio::spawn(connect_client(props));
-
-    test_transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeRequest(
-                AuthChallengeRequest {
-                    pubkey: pubkey_bytes,
-                },
-            )),
-        })
-        .await
-        .unwrap();
-
-    let response = test_transport
-        .recv()
-        .await
-        .expect("should receive challenge");
-    let challenge = match response {
-        Ok(resp) => match resp.payload {
-            Some(ClientResponsePayload::AuthChallenge(c)) => c,
-            other => panic!("Expected AuthChallenge, got {other:?}"),
-        },
-        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
-    };
-
-    let formatted_challenge = arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
-    let signature = new_key.sign(&formatted_challenge);
-
-    test_transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeSolution(
-                AuthChallengeSolution {
-                    signature: signature.to_bytes().to_vec(),
-                },
-            )),
-        })
-        .await
-        .unwrap();
-
-    task.await.unwrap();
-
-    let tx = TxEip1559 {
-        chain_id: 1,
-        nonce: 0,
-        gas_limit: 21_000,
-        max_fee_per_gas: 1,
-        max_priority_fee_per_gas: 1,
-        to: TxKind::Call(Address::from_slice(&[0x11; 20])),
-        value: U256::ZERO,
-        input: Bytes::new(),
-        access_list: Default::default(),
-    };
-
-    let mut rlp_transaction = Vec::new();
-    tx.encode(&mut rlp_transaction);
-
-    test_transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::EvmSignTransaction(
-                EvmSignTransactionRequest {
-                    wallet_address: [0x22; 20].to_vec(),
-                    rlp_transaction,
-                },
-            )),
-        })
-        .await
-        .unwrap();
-
-    let response = test_transport
-        .recv()
-        .await
-        .expect("should receive sign response");
-
-    match response {
-        Ok(resp) => match resp.payload {
-            Some(ClientResponsePayload::EvmSignTransaction(_)) => {}
-            other => panic!("Expected EvmSignTransaction response, got {other:?}"),
-        },
-        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
-    }
-}

server/crates/arbiter-server/tests/common/mod.rs

@@ -1,19 +1,19 @@
-use arbiter_proto::transport::{Bi, Error};
+use arbiter_proto::transport::{Bi, Error, Receiver, Sender};
 use arbiter_server::{
     actors::keyholder::KeyHolder,
     db::{self, schema},
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use async_trait::async_trait;
 use diesel::QueryDsl;
 use diesel_async::RunQueryDsl;
-use memsafe::MemSafe;
 use tokio::sync::mpsc;
 
 #[allow(dead_code)]
 pub async fn bootstrapped_keyholder(db: &db::DatabasePool) -> KeyHolder {
     let mut actor = KeyHolder::new(db.clone()).await.unwrap();
     actor
-        .bootstrap(MemSafe::new(b"test-seal-key".to_vec()).unwrap())
+        .bootstrap(SafeCell::new(b"test-seal-key".to_vec()))
         .await
         .unwrap();
     actor
@@ -55,10 +55,10 @@ impl<T, Y> ChannelTransport<T, Y> {
 }
 
 #[async_trait]
-impl<T, Y> Bi<T, Y> for ChannelTransport<T, Y>
+impl<T, Y> Sender<Y> for ChannelTransport<T, Y>
 where
-    T: Send + 'static,
-    Y: Send + 'static,
+    T: Send + Sync + 'static,
+    Y: Send + Sync + 'static,
 {
     async fn send(&mut self, item: Y) -> Result<(), Error> {
         self.sender
@@ -66,8 +66,22 @@ where
             .await
             .map_err(|_| Error::ChannelClosed)
     }
+}
 
+#[async_trait]
+impl<T, Y> Receiver<T> for ChannelTransport<T, Y>
+where
+    T: Send + Sync + 'static,
+    Y: Send + Sync + 'static,
+{
     async fn recv(&mut self) -> Option<T> {
         self.receiver.recv().await
     }
 }
+
+impl<T, Y> Bi<T, Y> for ChannelTransport<T, Y>
+where
+    T: Send + Sync + 'static,
+    Y: Send + Sync + 'static,
+{
+}

server/crates/arbiter-server/tests/keyholder/concurrency.rs

@@ -3,11 +3,11 @@ use std::collections::{HashMap, HashSet};
 use arbiter_server::{
     actors::keyholder::{CreateNew, Error, KeyHolder},
     db::{self, models, schema},
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper, dsl::sql_query};
 use diesel_async::RunQueryDsl;
 use kameo::actor::{ActorRef, Spawn as _};
-use memsafe::MemSafe;
 use tokio::task::JoinSet;
 
 use crate::common;
@@ -24,7 +24,7 @@ async fn write_concurrently(
             let plaintext = format!("{prefix}-{i}").into_bytes();
             let id = actor
                 .ask(CreateNew {
-                    plaintext: MemSafe::new(plaintext.clone()).unwrap(),
+                    plaintext: SafeCell::new(plaintext.clone()),
                 })
                 .await
                 .unwrap();
@@ -118,7 +118,7 @@ async fn insert_failure_does_not_create_partial_row() {
     drop(conn);
 
     let err = actor
-        .create_new(MemSafe::new(b"should fail".to_vec()).unwrap())
+        .create_new(SafeCell::new(b"should fail".to_vec()))
         .await
         .unwrap_err();
     assert!(matches!(err, Error::DatabaseTransaction(_)));
@@ -162,12 +162,12 @@ async fn decrypt_roundtrip_after_high_concurrency() {
 
     let mut decryptor = KeyHolder::new(db.clone()).await.unwrap();
     decryptor
-        .try_unseal(MemSafe::new(b"test-seal-key".to_vec()).unwrap())
+        .try_unseal(SafeCell::new(b"test-seal-key".to_vec()))
         .await
         .unwrap();
 
     for (id, plaintext) in expected {
         let mut decrypted = decryptor.decrypt(id).await.unwrap();
-        assert_eq!(*decrypted.read().unwrap(), plaintext);
+        assert_eq!(*decrypted.read(), plaintext);
     }
 }

server/crates/arbiter-server/tests/keyholder/lifecycle.rs

@@ -1,10 +1,10 @@
 use arbiter_server::{
     actors::keyholder::{Error, KeyHolder},
     db::{self, models, schema},
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use diesel::{QueryDsl, SelectableHelper};
 use diesel_async::RunQueryDsl;
-use memsafe::MemSafe;
 
 use crate::common;
 
@@ -14,7 +14,7 @@ async fn test_bootstrap() {
     let db = db::create_test_pool().await;
     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();
 
     let mut conn = db.get().await.unwrap();
@@ -43,7 +43,7 @@ async fn test_bootstrap_rejects_double() {
     let db = db::create_test_pool().await;
     let mut actor = common::bootstrapped_keyholder(&db).await;
 
-    let seal_key2 = MemSafe::new(b"test-seal-key".to_vec()).unwrap();
+    let seal_key2 = SafeCell::new(b"test-seal-key".to_vec());
     let err = actor.bootstrap(seal_key2).await.unwrap_err();
     assert!(matches!(err, Error::AlreadyBootstrapped));
 }
@@ -55,7 +55,7 @@ async fn test_create_new_before_bootstrap_fails() {
     let mut actor = KeyHolder::new(db).await.unwrap();
 
     let err = actor
-        .create_new(MemSafe::new(b"data".to_vec()).unwrap())
+        .create_new(SafeCell::new(b"data".to_vec()))
         .await
         .unwrap_err();
     assert!(matches!(err, Error::NotBootstrapped));
@@ -91,17 +91,17 @@ async fn test_unseal_correct_password() {
 
     let plaintext = b"survive a restart";
     let aead_id = actor
-        .create_new(MemSafe::new(plaintext.to_vec()).unwrap())
+        .create_new(SafeCell::new(plaintext.to_vec()))
         .await
         .unwrap();
     drop(actor);
 
     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.try_unseal(seal_key).await.unwrap();
 
     let mut decrypted = actor.decrypt(aead_id).await.unwrap();
-    assert_eq!(*decrypted.read().unwrap(), plaintext);
+    assert_eq!(*decrypted.read(), plaintext);
 }
 
 #[tokio::test]
@@ -112,20 +112,20 @@ async fn test_unseal_wrong_then_correct_password() {
 
     let plaintext = b"important data";
     let aead_id = actor
-        .create_new(MemSafe::new(plaintext.to_vec()).unwrap())
+        .create_new(SafeCell::new(plaintext.to_vec()))
         .await
         .unwrap();
     drop(actor);
 
     let mut actor = KeyHolder::new(db.clone()).await.unwrap();
 
-    let bad_key = MemSafe::new(b"wrong-password".to_vec()).unwrap();
+    let bad_key = SafeCell::new(b"wrong-password".to_vec());
     let err = actor.try_unseal(bad_key).await.unwrap_err();
     assert!(matches!(err, Error::InvalidKey));
 
-    let good_key = MemSafe::new(b"test-seal-key".to_vec()).unwrap();
+    let good_key = SafeCell::new(b"test-seal-key".to_vec());
     actor.try_unseal(good_key).await.unwrap();
 
     let mut decrypted = actor.decrypt(aead_id).await.unwrap();
-    assert_eq!(*decrypted.read().unwrap(), plaintext);
+    assert_eq!(*decrypted.read(), plaintext);
 }

server/crates/arbiter-server/tests/keyholder/storage.rs

@@ -3,10 +3,10 @@ use std::collections::HashSet;
 use arbiter_server::{
     actors::keyholder::{Error, encryption::v1},
     db::{self, models, schema},
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use diesel::{ExpressionMethods as _, QueryDsl, SelectableHelper, dsl::update};
 use diesel_async::RunQueryDsl;
-use memsafe::MemSafe;
 
 use crate::common;
 
@@ -18,12 +18,12 @@ async fn test_create_decrypt_roundtrip() {
 
     let plaintext = b"hello arbiter";
     let aead_id = actor
-        .create_new(MemSafe::new(plaintext.to_vec()).unwrap())
+        .create_new(SafeCell::new(plaintext.to_vec()))
         .await
         .unwrap();
 
     let mut decrypted = actor.decrypt(aead_id).await.unwrap();
-    assert_eq!(*decrypted.read().unwrap(), plaintext);
+    assert_eq!(*decrypted.read(), plaintext);
 }
 
 #[tokio::test]
@@ -44,11 +44,11 @@ async fn test_ciphertext_differs_across_entries() {
 
     let plaintext = b"same content";
     let id1 = actor
-        .create_new(MemSafe::new(plaintext.to_vec()).unwrap())
+        .create_new(SafeCell::new(plaintext.to_vec()))
         .await
         .unwrap();
     let id2 = actor
-        .create_new(MemSafe::new(plaintext.to_vec()).unwrap())
+        .create_new(SafeCell::new(plaintext.to_vec()))
         .await
         .unwrap();
 
@@ -70,8 +70,8 @@ async fn test_ciphertext_differs_across_entries() {
 
     let mut d1 = actor.decrypt(id1).await.unwrap();
     let mut d2 = actor.decrypt(id2).await.unwrap();
-    assert_eq!(*d1.read().unwrap(), plaintext);
-    assert_eq!(*d2.read().unwrap(), plaintext);
+    assert_eq!(*d1.read(), plaintext);
+    assert_eq!(*d2.read(), plaintext);
 }
 
 #[tokio::test]
@@ -83,7 +83,7 @@ async fn test_nonce_never_reused() {
     let n = 5;
     for i in 0..n {
         actor
-            .create_new(MemSafe::new(format!("secret {i}").into_bytes()).unwrap())
+            .create_new(SafeCell::new(format!("secret {i}").into_bytes()))
             .await
             .unwrap();
     }
@@ -137,7 +137,7 @@ async fn broken_db_nonce_format_fails_closed() {
     drop(conn);
 
     let err = actor
-        .create_new(MemSafe::new(b"must fail".to_vec()).unwrap())
+        .create_new(SafeCell::new(b"must fail".to_vec()))
         .await
         .unwrap_err();
     assert!(matches!(err, Error::BrokenDatabase));
@@ -145,7 +145,7 @@ async fn broken_db_nonce_format_fails_closed() {
     let db = db::create_test_pool().await;
     let mut actor = common::bootstrapped_keyholder(&db).await;
     let id = actor
-        .create_new(MemSafe::new(b"decrypt target".to_vec()).unwrap())
+        .create_new(SafeCell::new(b"decrypt target".to_vec()))
         .await
         .unwrap();
     let mut conn = db.get().await.unwrap();

server/crates/arbiter-server/tests/user_agent.rs

@@ -2,7 +2,5 @@ mod common;
 
 #[path = "user_agent/auth.rs"]
 mod auth;
-#[path = "user_agent/sdk_client.rs"]
-mod sdk_client;
 #[path = "user_agent/unseal.rs"]
 mod unseal;

server/crates/arbiter-server/tests/user_agent/auth.rs

@@ -1,14 +1,9 @@
-use arbiter_proto::proto::user_agent::{
-    AuthChallengeRequest, AuthChallengeSolution, KeyType as ProtoKeyType, UserAgentRequest,
-    user_agent_request::Payload as UserAgentRequestPayload,
-    user_agent_response::Payload as UserAgentResponsePayload,
-};
-use arbiter_proto::transport::Bi;
+use arbiter_proto::transport::{Receiver, Sender};
 use arbiter_server::{
     actors::{
         GlobalActors,
         bootstrap::GetToken,
-        user_agent::{UserAgentConnection, connect_user_agent},
+        user_agent::{AuthPublicKey, UserAgentConnection, auth},
     },
     db::{self, schema},
 };
@@ -26,26 +21,31 @@ pub async fn test_bootstrap_token_auth() {
     let token = actors.bootstrapper.ask(GetToken).await.unwrap().unwrap();
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
-    let props = UserAgentConnection::new(db.clone(), actors, Box::new(server_transport));
-    let task = tokio::spawn(connect_user_agent(props));
+    let db_for_task = db.clone();
+    let task = tokio::spawn(async move {
+        let mut props = UserAgentConnection::new(db_for_task, actors);
+        auth::authenticate(&mut props, server_transport).await
+    });
 
     let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
-
     test_transport
-        .send(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::AuthChallengeRequest(
-                AuthChallengeRequest {
-                    pubkey: pubkey_bytes,
-                    bootstrap_token: Some(token),
-                    key_type: ProtoKeyType::Ed25519.into(),
-                },
-            )),
+        .send(auth::Inbound::AuthChallengeRequest {
+            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+            bootstrap_token: Some(token),
         })
         .await
         .unwrap();
 
-    task.await.unwrap();
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive auth result");
+    match response {
+        Ok(auth::Outbound::AuthSuccess) => {}
+        other => panic!("Expected AuthSuccess, got {other:?}"),
+    }
+
+    task.await.unwrap().unwrap();
 
     let mut conn = db.get().await.unwrap();
     let stored_pubkey: Vec<u8> = schema::useragent_client::table
@@ -63,27 +63,25 @@ pub async fn test_bootstrap_invalid_token_auth() {
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
-    let props = UserAgentConnection::new(db.clone(), actors, Box::new(server_transport));
-    let task = tokio::spawn(connect_user_agent(props));
+    let db_for_task = db.clone();
+    let task = tokio::spawn(async move {
+        let mut props = UserAgentConnection::new(db_for_task, actors);
+        auth::authenticate(&mut props, server_transport).await
+    });
 
     let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
-
     test_transport
-        .send(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::AuthChallengeRequest(
-                AuthChallengeRequest {
-                    pubkey: pubkey_bytes,
-                    bootstrap_token: Some("invalid_token".to_string()),
-                    key_type: ProtoKeyType::Ed25519.into(),
-                },
-            )),
+        .send(auth::Inbound::AuthChallengeRequest {
+            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+            bootstrap_token: Some("invalid_token".to_string()),
         })
         .await
         .unwrap();
 
-    // Auth fails, connect_user_agent returns, transport drops
-    task.await.unwrap();
+    assert!(matches!(
+        task.await.unwrap(),
+        Err(auth::Error::InvalidBootstrapToken)
+    ));
 
     // Verify no key was registered
     let mut conn = db.get().await.unwrap();
@@ -118,19 +116,17 @@ pub async fn test_challenge_auth() {
     }
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
-    let props = UserAgentConnection::new(db.clone(), actors, Box::new(server_transport));
-    let task = tokio::spawn(connect_user_agent(props));
+    let db_for_task = db.clone();
+    let task = tokio::spawn(async move {
+        let mut props = UserAgentConnection::new(db_for_task, actors);
+        auth::authenticate(&mut props, server_transport).await
+    });
 
     // Send challenge request
     test_transport
-        .send(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::AuthChallengeRequest(
-                AuthChallengeRequest {
-                    pubkey: pubkey_bytes,
-                    bootstrap_token: None,
-                    key_type: ProtoKeyType::Ed25519.into(),
-                },
-            )),
+        .send(auth::Inbound::AuthChallengeRequest {
+            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+            bootstrap_token: None,
         })
         .await
         .unwrap();
@@ -141,28 +137,31 @@ pub async fn test_challenge_auth() {
         .await
         .expect("should receive challenge");
     let challenge = match response {
-        Ok(resp) => match resp.payload {
-            Some(UserAgentResponsePayload::AuthChallenge(c)) => c,
+        Ok(resp) => match resp {
+            auth::Outbound::AuthChallenge { nonce } => nonce,
             other => panic!("Expected AuthChallenge, got {other:?}"),
         },
         Err(err) => panic!("Expected Ok response, got Err({err:?})"),
     };
 
-    // Sign the challenge and send solution
-    let formatted_challenge = arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
+    let formatted_challenge = arbiter_proto::format_challenge(challenge, &pubkey_bytes);
     let signature = new_key.sign(&formatted_challenge);
 
     test_transport
-        .send(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::AuthChallengeSolution(
-                AuthChallengeSolution {
-                    signature: signature.to_bytes().to_vec(),
-                },
-            )),
+        .send(auth::Inbound::AuthChallengeSolution {
+            signature: signature.to_bytes().to_vec(),
         })
         .await
         .unwrap();
 
-    // Auth completes, session spawned
-    task.await.unwrap();
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive auth result");
+    match response {
+        Ok(auth::Outbound::AuthSuccess) => {}
+        other => panic!("Expected AuthSuccess, got {other:?}"),
+    }
+
+    task.await.unwrap().unwrap();
 }

server/crates/arbiter-server/tests/user_agent/sdk_client.rs

@@ -1,270 +0,0 @@
-use arbiter_proto::proto::user_agent::{
-    SdkClientApproveRequest, SdkClientError as ProtoSdkClientError, SdkClientRevokeRequest,
-    UserAgentRequest, 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 arbiter_server::{
-    actors::{GlobalActors, user_agent::session::UserAgentSession},
-    db,
-};
-
-/// Shared helper: create a session and register a client pubkey via sdk_client_approve.
-async fn make_session(db: &db::DatabasePool) -> UserAgentSession {
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-    UserAgentSession::new_test(db.clone(), actors)
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_approve_registers_client() {
-    let db = db::create_test_pool().await;
-    let mut session = make_session(&db).await;
-
-    let pubkey = [0x42u8; 32];
-
-    let response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientApprove(
-                SdkClientApproveRequest {
-                    pubkey: pubkey.to_vec(),
-                },
-            )),
-        })
-        .await
-        .expect("handler should succeed");
-
-    let entry = match response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientApprove(resp) => match resp.result.unwrap() {
-            sdk_client_approve_response::Result::Client(e) => e,
-            sdk_client_approve_response::Result::Error(e) => {
-                panic!("Expected Client, got error {:?}", e)
-            }
-        },
-        other => panic!("Expected SdkClientApprove, got {other:?}"),
-    };
-
-    assert_eq!(entry.pubkey, pubkey.to_vec());
-    assert!(entry.id > 0);
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_approve_duplicate_returns_already_exists() {
-    let db = db::create_test_pool().await;
-    let mut session = make_session(&db).await;
-
-    let pubkey = [0x11u8; 32];
-    let req = UserAgentRequest {
-        payload: Some(UserAgentRequestPayload::SdkClientApprove(
-            SdkClientApproveRequest {
-                pubkey: pubkey.to_vec(),
-            },
-        )),
-    };
-
-    session
-        .process_transport_inbound(req.clone())
-        .await
-        .unwrap();
-
-    let response = session
-        .process_transport_inbound(req)
-        .await
-        .expect("second insert should not panic");
-
-    match response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientApprove(resp) => match resp.result.unwrap() {
-            sdk_client_approve_response::Result::Error(code) => {
-                assert_eq!(code, ProtoSdkClientError::AlreadyExists as i32);
-            }
-            sdk_client_approve_response::Result::Client(_) => {
-                panic!("Expected AlreadyExists error for duplicate pubkey")
-            }
-        },
-        other => panic!("Expected SdkClientApprove, got {other:?}"),
-    }
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_list_shows_registered_clients() {
-    let db = db::create_test_pool().await;
-    let mut session = make_session(&db).await;
-
-    let pubkey_a = [0x0Au8; 32];
-    let pubkey_b = [0x0Bu8; 32];
-
-    for pubkey in [pubkey_a, pubkey_b] {
-        session
-            .process_transport_inbound(UserAgentRequest {
-                payload: Some(UserAgentRequestPayload::SdkClientApprove(
-                    SdkClientApproveRequest {
-                        pubkey: pubkey.to_vec(),
-                    },
-                )),
-            })
-            .await
-            .unwrap();
-    }
-
-    let response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientList(())),
-        })
-        .await
-        .expect("list should succeed");
-
-    let clients = match response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientList(resp) => match resp.result.unwrap() {
-            sdk_client_list_response::Result::Clients(list) => list.clients,
-            sdk_client_list_response::Result::Error(e) => {
-                panic!("Expected Clients, got error {:?}", e)
-            }
-        },
-        other => panic!("Expected SdkClientList, got {other:?}"),
-    };
-
-    assert_eq!(clients.len(), 2);
-    let pubkeys: Vec<Vec<u8>> = clients.into_iter().map(|e| e.pubkey).collect();
-    assert!(pubkeys.contains(&pubkey_a.to_vec()));
-    assert!(pubkeys.contains(&pubkey_b.to_vec()));
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_revoke_removes_client() {
-    let db = db::create_test_pool().await;
-    let mut session = make_session(&db).await;
-
-    let pubkey = [0xBBu8; 32];
-
-    // Register a client and get its id
-    let approve_response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientApprove(
-                SdkClientApproveRequest {
-                    pubkey: pubkey.to_vec(),
-                },
-            )),
-        })
-        .await
-        .unwrap();
-
-    let client_id = match approve_response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientApprove(resp) => match resp.result.unwrap() {
-            sdk_client_approve_response::Result::Client(e) => e.id,
-            sdk_client_approve_response::Result::Error(e) => panic!("approve failed: {:?}", e),
-        },
-        other => panic!("{other:?}"),
-    };
-
-    // Revoke the client
-    let revoke_response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientRevoke(
-                SdkClientRevokeRequest { client_id },
-            )),
-        })
-        .await
-        .expect("revoke should succeed");
-
-    match revoke_response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientRevoke(resp) => match resp.result.unwrap() {
-            sdk_client_revoke_response::Result::Ok(_) => {}
-            sdk_client_revoke_response::Result::Error(e) => {
-                panic!("Expected Ok, got error {:?}", e)
-            }
-        },
-        other => panic!("Expected SdkClientRevoke, got {other:?}"),
-    }
-
-    // List should now be empty
-    let list_response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientList(())),
-        })
-        .await
-        .unwrap();
-
-    let clients = match list_response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientList(resp) => match resp.result.unwrap() {
-            sdk_client_list_response::Result::Clients(list) => list.clients,
-            sdk_client_list_response::Result::Error(e) => panic!("list error: {:?}", e),
-        },
-        other => panic!("{other:?}"),
-    };
-    assert!(clients.is_empty(), "client should be removed after revoke");
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_revoke_not_found_returns_error() {
-    let db = db::create_test_pool().await;
-    let mut session = make_session(&db).await;
-
-    let response = session
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::SdkClientRevoke(
-                SdkClientRevokeRequest { client_id: 9999 },
-            )),
-        })
-        .await
-        .unwrap();
-
-    match response.payload.unwrap() {
-        UserAgentResponsePayload::SdkClientRevoke(resp) => match resp.result.unwrap() {
-            sdk_client_revoke_response::Result::Error(code) => {
-                assert_eq!(code, ProtoSdkClientError::NotFound as i32);
-            }
-            sdk_client_revoke_response::Result::Ok(_) => {
-                panic!("Expected NotFound error for missing client_id")
-            }
-        },
-        other => panic!("Expected SdkClientRevoke, got {other:?}"),
-    }
-}
-
-#[tokio::test]
-#[test_log::test]
-async fn test_sdk_client_approve_rejected_client_cannot_auth() {
-    // Verify the core flow: only pre-approved clients can authenticate
-    use arbiter_proto::proto::client::{
-        AuthChallengeRequest, ClientRequest, client_request::Payload as ClientRequestPayload,
-        client_response::Payload as ClientResponsePayload,
-    };
-    use arbiter_proto::transport::Bi as _;
-    use arbiter_server::actors::client::{ClientConnection, connect_client};
-
-    let db = db::create_test_pool().await;
-    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
-
-    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
-    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
-
-    let (server_transport, mut test_transport) = super::common::ChannelTransport::<_, _>::new();
-    let props = ClientConnection::new(db.clone(), Box::new(server_transport), actors.clone());
-    let task = tokio::spawn(connect_client(props));
-
-    test_transport
-        .send(ClientRequest {
-            payload: Some(ClientRequestPayload::AuthChallengeRequest(
-                AuthChallengeRequest {
-                    pubkey: pubkey_bytes.clone(),
-                },
-            )),
-        })
-        .await
-        .unwrap();
-
-    let response = test_transport.recv().await.unwrap().unwrap();
-    assert!(
-        matches!(
-            response.payload.unwrap(),
-            ClientResponsePayload::ClientConnectError(_)
-        ),
-        "unregistered client should be rejected"
-    );
-
-    task.await.unwrap();
-}

server/crates/arbiter-server/tests/user_agent/unseal.rs

@@ -1,63 +1,55 @@
-use arbiter_proto::proto::user_agent::{
-    UnsealEncryptedKey, UnsealResult, UnsealStart, UserAgentRequest,
-    user_agent_request::Payload as UserAgentRequestPayload,
-    user_agent_response::Payload as UserAgentResponsePayload,
-};
 use arbiter_server::{
     actors::{
         GlobalActors,
         keyholder::{Bootstrap, Seal},
-        user_agent::session::UserAgentSession,
+        user_agent::session::{
+            HandleUnsealEncryptedKey, HandleUnsealRequest, UnsealError, UserAgentSession,
+        },
     },
     db,
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
-use memsafe::MemSafe;
+use kameo::actor::Spawn as _;
 use x25519_dalek::{EphemeralSecret, PublicKey};
 
 async fn setup_sealed_user_agent(
     seal_key: &[u8],
-) -> (db::DatabasePool, UserAgentSession) {
+) -> (db::DatabasePool, kameo::actor::ActorRef<UserAgentSession>) {
     let db = db::create_test_pool().await;
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
     actors
         .key_holder
         .ask(Bootstrap {
-            seal_key_raw: MemSafe::new(seal_key.to_vec()).unwrap(),
+            seal_key_raw: SafeCell::new(seal_key.to_vec()),
         })
         .await
         .unwrap();
     actors.key_holder.ask(Seal).await.unwrap();
 
-    let session = UserAgentSession::new_test(db.clone(), actors);
+    let session = UserAgentSession::spawn(UserAgentSession::new_test(db.clone(), actors));
 
     (db, session)
 }
 
 async fn client_dh_encrypt(
-    user_agent: &mut UserAgentSession,
+    user_agent: &kameo::actor::ActorRef<UserAgentSession>,
     key_to_send: &[u8],
-) -> UnsealEncryptedKey {
+) -> HandleUnsealEncryptedKey {
     let client_secret = EphemeralSecret::random();
     let client_public = PublicKey::from(&client_secret);
 
     let response = user_agent
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::UnsealStart(UnsealStart {
-                client_pubkey: client_public.as_bytes().to_vec(),
-            })),
+        .ask(HandleUnsealRequest {
+            client_pubkey: client_public,
         })
         .await
         .unwrap();
 
-    let server_pubkey = match response.payload.unwrap() {
-        UserAgentResponsePayload::UnsealStartResponse(resp) => resp.server_pubkey,
-        other => panic!("Expected UnsealStartResponse, got {other:?}"),
-    };
-    let server_public = PublicKey::from(<[u8; 32]>::try_from(server_pubkey.as_slice()).unwrap());
+    let server_pubkey = response.server_pubkey;
 
-    let shared_secret = client_secret.diffie_hellman(&server_public);
+    let shared_secret = client_secret.diffie_hellman(&server_pubkey);
     let cipher = XChaCha20Poly1305::new(shared_secret.as_bytes().into());
     let nonce = XNonce::from([0u8; 24]);
     let associated_data = b"unseal";
@@ -66,119 +58,94 @@ async fn client_dh_encrypt(
         .encrypt_in_place(&nonce, associated_data, &mut ciphertext)
         .unwrap();
 
-    UnsealEncryptedKey {
+    HandleUnsealEncryptedKey {
         nonce: nonce.to_vec(),
         ciphertext,
         associated_data: associated_data.to_vec(),
     }
 }
 
-fn unseal_key_request(req: UnsealEncryptedKey) -> UserAgentRequest {
-    UserAgentRequest {
-        payload: Some(UserAgentRequestPayload::UnsealEncryptedKey(req)),
-    }
-}
-
 #[tokio::test]
 #[test_log::test]
 pub async fn test_unseal_success() {
     let seal_key = b"test-seal-key";
-    let (_db, mut user_agent) = setup_sealed_user_agent(seal_key).await;
+    let (_db, user_agent) = setup_sealed_user_agent(seal_key).await;
 
-    let encrypted_key = client_dh_encrypt(&mut user_agent, seal_key).await;
+    let encrypted_key = client_dh_encrypt(&user_agent, seal_key).await;
 
-    let response = user_agent
-        .process_transport_inbound(unseal_key_request(encrypted_key))
-        .await
-        .unwrap();
-
-    assert_eq!(
-        response.payload.unwrap(),
-        UserAgentResponsePayload::UnsealResult(UnsealResult::Success.into()),
-    );
+    let response = user_agent.ask(encrypted_key).await;
+    assert!(matches!(response, Ok(())));
 }
 
 #[tokio::test]
 #[test_log::test]
 pub async fn test_unseal_wrong_seal_key() {
-    let (_db, mut user_agent) = setup_sealed_user_agent(b"correct-key").await;
+    let (_db, user_agent) = setup_sealed_user_agent(b"correct-key").await;
 
-    let encrypted_key = client_dh_encrypt(&mut user_agent, b"wrong-key").await;
+    let encrypted_key = client_dh_encrypt(&user_agent, b"wrong-key").await;
 
-    let response = user_agent
-        .process_transport_inbound(unseal_key_request(encrypted_key))
-        .await
-        .unwrap();
-
-    assert_eq!(
-        response.payload.unwrap(),
-        UserAgentResponsePayload::UnsealResult(UnsealResult::InvalidKey.into()),
-    );
+    let response = user_agent.ask(encrypted_key).await;
+    assert!(matches!(
+        response,
+        Err(kameo::error::SendError::HandlerError(
+            UnsealError::InvalidKey
+        ))
+    ));
 }
 
 #[tokio::test]
 #[test_log::test]
 pub async fn test_unseal_corrupted_ciphertext() {
-    let (_db, mut user_agent) = setup_sealed_user_agent(b"test-key").await;
+    let (_db, user_agent) = setup_sealed_user_agent(b"test-key").await;
 
     let client_secret = EphemeralSecret::random();
     let client_public = PublicKey::from(&client_secret);
 
     user_agent
-        .process_transport_inbound(UserAgentRequest {
-            payload: Some(UserAgentRequestPayload::UnsealStart(UnsealStart {
-                client_pubkey: client_public.as_bytes().to_vec(),
-            })),
+        .ask(HandleUnsealRequest {
+            client_pubkey: client_public,
         })
         .await
         .unwrap();
 
     let response = user_agent
-        .process_transport_inbound(unseal_key_request(UnsealEncryptedKey {
+        .ask(HandleUnsealEncryptedKey {
             nonce: vec![0u8; 24],
             ciphertext: vec![0u8; 32],
             associated_data: vec![],
-        }))
-        .await
-        .unwrap();
+        })
+        .await;
 
-    assert_eq!(
-        response.payload.unwrap(),
-        UserAgentResponsePayload::UnsealResult(UnsealResult::InvalidKey.into()),
-    );
+    assert!(matches!(
+        response,
+        Err(kameo::error::SendError::HandlerError(
+            UnsealError::InvalidKey
+        ))
+    ));
 }
 
 #[tokio::test]
 #[test_log::test]
 pub async fn test_unseal_retry_after_invalid_key() {
     let seal_key = b"real-seal-key";
-    let (_db, mut user_agent) = setup_sealed_user_agent(seal_key).await;
+    let (_db, user_agent) = setup_sealed_user_agent(seal_key).await;
 
     {
-        let encrypted_key = client_dh_encrypt(&mut user_agent, b"wrong-key").await;
+        let encrypted_key = client_dh_encrypt(&user_agent, b"wrong-key").await;
 
-        let response = user_agent
-            .process_transport_inbound(unseal_key_request(encrypted_key))
-            .await
-            .unwrap();
-
-        assert_eq!(
-            response.payload.unwrap(),
-            UserAgentResponsePayload::UnsealResult(UnsealResult::InvalidKey.into()),
-        );
+        let response = user_agent.ask(encrypted_key).await;
+        assert!(matches!(
+            response,
+            Err(kameo::error::SendError::HandlerError(
+                UnsealError::InvalidKey
+            ))
+        ));
     }
 
     {
-        let encrypted_key = client_dh_encrypt(&mut user_agent, seal_key).await;
+        let encrypted_key = client_dh_encrypt(&user_agent, seal_key).await;
 
-        let response = user_agent
-            .process_transport_inbound(unseal_key_request(encrypted_key))
-            .await
-            .unwrap();
-
-        assert_eq!(
-            response.payload.unwrap(),
-            UserAgentResponsePayload::UnsealResult(UnsealResult::Success.into()),
-        );
+        let response = user_agent.ask(encrypted_key).await;
+        assert!(matches!(response, Ok(())));
     }
 }

server/crates/arbiter-terrors-poc/Cargo.toml

@@ -1,7 +0,0 @@
-[package]
-name = "arbiter-terrors-poc"
-version = "0.1.0"
-edition = "2024"
-
-[dependencies]
-terrors = "0.3"

server/crates/arbiter-terrors-poc/src/auth.rs

@@ -1,139 +0,0 @@
-use crate::errors::{InternalError1, InternalError2, InvalidSignature, NotRegistered};
-use terrors::OneOf;
-
-use crate::errors::ProtoError;
-
-// Each sub-call's error type already implements DrainInto<ProtoError>, so we convert
-// directly to ProtoError without broaden — no turbofish needed anywhere.
-//
-// Call chain:
-//   load_config()  → OneOf<(InternalError2,)>          → ProtoError::from
-//   get_nonce()    → OneOf<(InternalError1, InternalError2)> → ProtoError::from
-//   verify_sig()   → OneOf<(InvalidSignature,)>         → ProtoError::from
-pub fn process_request(id: u32, sig: &str) -> Result<String, ProtoError> {
-    if id == 0 {
-        return Err(ProtoError::NotRegistered);
-    }
-
-    let config = load_config(id).map_err(ProtoError::from)?;
-    let nonce = crate::db::get_nonce(id).map_err(ProtoError::from)?;
-    verify_signature(nonce, sig).map_err(ProtoError::from)?;
-
-    Ok(format!("config={config} nonce={nonce} sig={sig}"))
-}
-
-// Simulates loading a config value.
-// id=97 triggers InternalError2 ("config read failed").
-fn load_config(id: u32) -> Result<String, OneOf<(InternalError2,)>> {
-    if id == 97 {
-        return Err(OneOf::new(InternalError2("config read failed".to_owned())));
-    }
-    Ok(format!("cfg-{id}"))
-}
-
-pub fn verify_signature(_nonce: u32, sig: &str) -> Result<(), OneOf<(InvalidSignature,)>> {
-    if sig != "ok" {
-        return Err(OneOf::new(InvalidSignature));
-    }
-    Ok(())
-}
-
-type AuthError = OneOf<(
-    NotRegistered,
-    InvalidSignature,
-    InternalError1,
-    InternalError2,
-)>;
-
-pub fn authenticate(id: u32, sig: &str) -> Result<u32, AuthError> {
-    if id == 0 {
-        return Err(OneOf::new(NotRegistered));
-    }
-
-    // Return type AuthError lets the compiler infer the broaden target.
-    let nonce = crate::db::get_nonce(id).map_err(OneOf::broaden)?;
-    verify_signature(nonce, sig).map_err(OneOf::broaden)?;
-
-    Ok(nonce)
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn verify_signature_ok() {
-        assert!(verify_signature(42, "ok").is_ok());
-    }
-
-    #[test]
-    fn verify_signature_bad() {
-        let err = verify_signature(42, "bad").unwrap_err();
-        assert!(err.narrow::<crate::errors::InvalidSignature, _>().is_ok());
-    }
-
-    #[test]
-    fn authenticate_success() {
-        assert_eq!(authenticate(1, "ok").unwrap(), 42);
-    }
-
-    #[test]
-    fn authenticate_not_registered() {
-        let err = authenticate(0, "ok").unwrap_err();
-        assert!(err.narrow::<crate::errors::NotRegistered, _>().is_ok());
-    }
-
-    #[test]
-    fn authenticate_invalid_signature() {
-        let err = authenticate(1, "bad").unwrap_err();
-        assert!(err.narrow::<crate::errors::InvalidSignature, _>().is_ok());
-    }
-
-    #[test]
-    fn authenticate_internal_error1() {
-        let err = authenticate(99, "ok").unwrap_err();
-        assert!(err.narrow::<crate::errors::InternalError1, _>().is_ok());
-    }
-
-    #[test]
-    fn authenticate_internal_error2() {
-        let err = authenticate(98, "ok").unwrap_err();
-        assert!(err.narrow::<crate::errors::InternalError2, _>().is_ok());
-    }
-
-    #[test]
-    fn process_request_success() {
-        let result = process_request(1, "ok").unwrap();
-        assert!(result.contains("nonce=42"));
-    }
-
-    #[test]
-    fn process_request_not_registered() {
-        let err = process_request(0, "ok").unwrap_err();
-        assert!(matches!(err, crate::errors::ProtoError::NotRegistered));
-    }
-
-    #[test]
-    fn process_request_invalid_signature() {
-        let err = process_request(1, "bad").unwrap_err();
-        assert!(matches!(err, crate::errors::ProtoError::InvalidSignature));
-    }
-
-    #[test]
-    fn process_request_internal_from_config() {
-        // id=97 → load_config returns InternalError2
-        let err = process_request(97, "ok").unwrap_err();
-        assert!(
-            matches!(err, crate::errors::ProtoError::Internal(ref msg) if msg == "config read failed")
-        );
-    }
-
-    #[test]
-    fn process_request_internal_from_db() {
-        // id=99 → get_nonce returns InternalError1
-        let err = process_request(99, "ok").unwrap_err();
-        assert!(
-            matches!(err, crate::errors::ProtoError::Internal(ref msg) if msg == "db pool unavailable")
-        );
-    }
-}

server/crates/arbiter-terrors-poc/src/db.rs

@@ -1,38 +0,0 @@
-use crate::errors::{InternalError1, InternalError2};
-use terrors::OneOf;
-
-// Simulates fetching a nonce from a database.
-// id=99 → InternalError1 (pool unavailable)
-// id=98 → InternalError2 (query timeout)
-pub fn get_nonce(id: u32) -> Result<u32, OneOf<(InternalError1, InternalError2)>> {
-    match id {
-        99 => Err(OneOf::new(InternalError1("db pool unavailable".to_owned()))),
-        98 => Err(OneOf::new(InternalError2("query timeout".to_owned()))),
-        _ => Ok(42),
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn get_nonce_returns_nonce_for_valid_id() {
-        assert_eq!(get_nonce(1).unwrap(), 42);
-    }
-
-    #[test]
-    fn get_nonce_returns_internal_error1_for_sentinel() {
-        let err = get_nonce(99).unwrap_err();
-        let internal = err.narrow::<crate::errors::InternalError1, _>().unwrap();
-        assert_eq!(internal.0, "db pool unavailable");
-    }
-
-    #[test]
-    fn get_nonce_returns_internal_error2_for_sentinel() {
-        let err = get_nonce(98).unwrap_err();
-        let e = err.narrow::<crate::errors::InternalError1, _>().unwrap_err();
-        let internal = e.take::<crate::errors::InternalError2>();
-        assert_eq!(internal.0, "query timeout");
-    }
-}

server/crates/arbiter-terrors-poc/src/errors.rs

@@ -1,130 +0,0 @@
-use terrors::OneOf;
-
-// Wire boundary type — what would go into a proto response
-#[derive(Debug)]
-pub enum ProtoError {
-    NotRegistered,
-    InvalidSignature,
-    Internal(String), // Or Box<dyn Error>, who cares?
-}
-
-// Internal terrors types
-#[derive(Debug)]
-pub struct NotRegistered;
-#[derive(Debug)]
-pub struct InvalidSignature;
-#[derive(Debug)]
-pub struct InternalError1(pub String);
-#[derive(Debug)]
-pub struct InternalError2(pub String);
-
-// Errors can be scattered across the codebase as long as they implement Into<ProtoError>
-impl From<NotRegistered> for ProtoError {
-    fn from(_: NotRegistered) -> Self {
-        ProtoError::NotRegistered
-    }
-}
-
-impl From<InvalidSignature> for ProtoError {
-    fn from(_: InvalidSignature) -> Self {
-        ProtoError::InvalidSignature
-    }
-}
-
-impl From<InternalError1> for ProtoError {
-    fn from(e: InternalError1) -> Self {
-        ProtoError::Internal(e.0)
-    }
-}
-impl From<InternalError2> for ProtoError {
-    fn from(e: InternalError2) -> Self {
-        ProtoError::Internal(e.0)
-    }
-}
-
-/// Private helper trait for converting from OneOf<T...> where each T can be converted
-/// into the target type `O` by recursively narrowing until a match is found.
-/// 
-/// IDK why this isn't already in terrors.
-trait DrainInto<O>: terrors::TypeSet + Sized {
-    fn drain(e: OneOf<Self>) -> O;
-}
-
-macro_rules! impl_drain_into {
-    ($head:ident) => {
-        impl<$head, O> DrainInto<O> for ($head,)
-        where
-            $head: Into<O> + 'static,
-        {
-            fn drain(e: OneOf<($head,)>) -> O {
-                e.take().into()
-            }
-        }
-    };
-    ($head:ident, $($tail:ident),+) => {
-        impl<$head, $($tail),+, O> DrainInto<O> for ($head, $($tail),+)
-        where
-            $head: Into<O> + 'static,
-            ($($tail,)+): DrainInto<O>,
-        {
-            fn drain(e: OneOf<($head, $($tail),+)>) -> O {
-                match e.narrow::<$head, _>() {
-                    Ok(h) => h.into(),
-                    Err(rest) => <($($tail,)+)>::drain(rest),
-                }
-            }
-        }
-        impl_drain_into!($($tail),+);
-    };
-}
-
-// Generates impls for all tuple sizes from 1 up to 7 (restricted by terrors internal impl).
-// Each invocation produces one impl then recurses on the tail.
-impl_drain_into!(A, B, C, D, E, F, G, H, I);
-
-// Blanket From impl: body delegates to the recursive drain.
-impl<E: DrainInto<ProtoError>> From<OneOf<E>> for ProtoError {
-    fn from(e: OneOf<E>) -> Self {
-        E::drain(e)
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn not_registered_converts_to_proto() {
-        let e: ProtoError = NotRegistered.into();
-        assert!(matches!(e, ProtoError::NotRegistered));
-    }
-
-    #[test]
-    fn invalid_signature_converts_to_proto() {
-        let e: ProtoError = InvalidSignature.into();
-        assert!(matches!(e, ProtoError::InvalidSignature));
-    }
-
-    #[test]
-    fn internal_converts_to_proto() {
-        let e: ProtoError = InternalError1("boom".into()).into();
-        assert!(matches!(e, ProtoError::Internal(msg) if msg == "boom"));
-    }
-
-    #[test]
-    fn one_of_remainder_converts_to_proto_invalid_signature() {
-        use terrors::OneOf;
-        let e: OneOf<(InvalidSignature, InternalError1)> = OneOf::new(InvalidSignature);
-        let proto = ProtoError::from(e);
-        assert!(matches!(proto, ProtoError::InvalidSignature));
-    }
-
-    #[test]
-    fn one_of_remainder_converts_to_proto_internal() {
-        use terrors::OneOf;
-        let e: OneOf<(InvalidSignature, InternalError1)> =
-            OneOf::new(InternalError1("db fail".into()));
-        let proto = ProtoError::from(e);
-        assert!(matches!(proto, ProtoError::Internal(msg) if msg == "db fail"));
-    }
-}

server/crates/arbiter-terrors-poc/src/main.rs

@@ -1,43 +0,0 @@
-mod auth;
-mod db;
-mod errors;
-
-use errors::ProtoError;
-
-fn run(id: u32, sig: &str) {
-    print!("authenticate(id={id}, sig={sig:?}) => ");
-    match auth::authenticate(id, sig) {
-        Ok(nonce) => println!("Ok(nonce={nonce})"),
-        Err(e) => match e.narrow::<errors::NotRegistered, _>() {
-            Ok(_) => println!("Err(NotRegistered) — handled locally"),
-            Err(remaining) => {
-                let proto = ProtoError::from(remaining);
-                println!("Err(ProtoError::{proto:?}) — forwarded to wire");
-            }
-        },
-    }
-}
-
-fn run_process(id: u32, sig: &str) {
-    print!("process_request(id={id}, sig={sig:?}) => ");
-    match auth::process_request(id, sig) {
-        Ok(s) => println!("Ok({s})"),
-        Err(e) => println!("Err(ProtoError::{e:?})"),
-    }
-}
-
-fn main() {
-    println!("=== authenticate ===");
-    run(0, "ok");   // NotRegistered
-    run(1, "bad");  // InvalidSignature
-    run(99, "ok");  // InternalError1
-    run(98, "ok");  // InternalError2
-    run(1, "ok");   // success
-
-    println!("\n=== process_request (Try chain) ===");
-    run_process(0, "ok");   // NotRegistered (guard, no I/O)
-    run_process(97, "ok");  // InternalError2 from load_config
-    run_process(99, "ok");  // InternalError1 from get_nonce
-    run_process(1, "bad");  // InvalidSignature from verify_signature
-    run_process(1, "ok");   // success
-}

server/crates/arbiter-useragent/Cargo.toml

@@ -1,29 +0,0 @@
-[package]
-name = "arbiter-useragent"
-version = "0.1.0"
-edition = "2024"
-license = "Apache-2.0"
-
-[lints]
-workspace = true
-
-[dependencies]
-arbiter-proto.path = "../arbiter-proto"
-kameo.workspace = true
-tokio = {workspace = true, features = ["net"]}
-tonic.workspace = true
-tonic.features = ["tls-aws-lc"]
-tracing.workspace = true
-ed25519-dalek.workspace = true
-smlang.workspace = true
-x25519-dalek.workspace = true
-k256.workspace = true
-rsa.workspace = true
-sha2.workspace = true
-spki.workspace = true
-rand.workspace = true
-thiserror.workspace = true
-tokio-stream.workspace = true
-http = "1.4.0"
-rustls-webpki = { version = "0.103.9", features = ["aws-lc-rs"] }
-async-trait.workspace = true

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

@@ -1,70 +0,0 @@
-use arbiter_proto::{
-    proto::{
-        arbiter_service_client::ArbiterServiceClient,
-        user_agent::{UserAgentRequest, UserAgentResponse},
-    },
-    transport::{IdentityRecvConverter, IdentitySendConverter, grpc},
-    url::ArbiterUrl,
-};
-use kameo::actor::{ActorRef, Spawn};
-
-use tokio::sync::mpsc;
-use tokio_stream::wrappers::ReceiverStream;
-
-use tonic::transport::ClientTlsConfig;
-
-use super::{SigningKeyEnum, UserAgentActor};
-
-#[derive(Debug, thiserror::Error)]
-pub enum ConnectError {
-    #[error("Could 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("gRPC error")]
-    Grpc(#[from] tonic::Status),
-}
-
-pub type UserAgentGrpc = ActorRef<
-    UserAgentActor<
-        grpc::GrpcAdapter<
-            IdentityRecvConverter<UserAgentResponse>,
-            IdentitySendConverter<UserAgentRequest>,
-        >,
-    >,
->;
-pub async fn connect_grpc(
-    url: ArbiterUrl,
-    key: SigningKeyEnum,
-) -> Result<UserAgentGrpc, ConnectError> {
-    let bootstrap_token = url.bootstrap_token.clone();
-    let anchor = webpki::anchor_from_trusted_cert(&url.ca_cert)?.to_owned();
-    let tls = ClientTlsConfig::new().trust_anchor(anchor);
-
-    // TODO: if `host` is localhost, we need to verify server's process authenticity
-    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 bistream = client.user_agent(ReceiverStream::new(rx)).await?;
-    let bistream = bistream.into_inner();
-
-    let adapter = grpc::GrpcAdapter::new(
-        tx,
-        bistream,
-        IdentityRecvConverter::new(),
-        IdentitySendConverter::new(),
-    );
-
-    let actor = UserAgentActor::spawn(UserAgentActor::new(key, bootstrap_token, adapter));
-
-    Ok(actor)
-}

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

@@ -1,257 +0,0 @@
-use arbiter_proto::{
-    format_challenge,
-    proto::user_agent::{
-        AuthChallengeRequest, AuthChallengeSolution, AuthOk, KeyType as ProtoKeyType,
-        UserAgentRequest, UserAgentResponse,
-        user_agent_request::Payload as UserAgentRequestPayload,
-        user_agent_response::Payload as UserAgentResponsePayload,
-    },
-    transport::Bi,
-};
-use kameo::{Actor, actor::ActorRef};
-use smlang::statemachine;
-use tokio::select;
-use tracing::{error, info};
-
-/// Signing key variants supported by the user-agent auth protocol.
-pub enum SigningKeyEnum {
-    Ed25519(ed25519_dalek::SigningKey),
-    /// secp256k1 ECDSA; public key is sent as SEC1 compressed 33 bytes; signature is raw 64-byte (r||s).
-    EcdsaSecp256k1(k256::ecdsa::SigningKey),
-    /// RSA for Windows Hello (KeyCredentialManager); public key is DER SPKI; signature is PSS+SHA-256.
-    Rsa(rsa::RsaPrivateKey),
-}
-
-impl SigningKeyEnum {
-    /// Returns the canonical public key bytes to include in `AuthChallengeRequest.pubkey`.
-    pub fn pubkey_bytes(&self) -> Vec<u8> {
-        match self {
-            SigningKeyEnum::Ed25519(k) => k.verifying_key().to_bytes().to_vec(),
-            // 33-byte SEC1 compressed point — compact and natively supported by secp256k1 tooling
-            SigningKeyEnum::EcdsaSecp256k1(k) => {
-                k.verifying_key().to_encoded_point(true).as_bytes().to_vec()
-            }
-            SigningKeyEnum::Rsa(k) => {
-                use rsa::pkcs8::EncodePublicKey as _;
-                k.to_public_key()
-                    .to_public_key_der()
-                    .expect("rsa SPKI encoding is infallible")
-                    .to_vec()
-            }
-        }
-    }
-
-    /// Returns the proto `KeyType` discriminant to send in `AuthChallengeRequest.key_type`.
-    pub fn proto_key_type(&self) -> ProtoKeyType {
-        match self {
-            SigningKeyEnum::Ed25519(_) => ProtoKeyType::Ed25519,
-            SigningKeyEnum::EcdsaSecp256k1(_) => ProtoKeyType::EcdsaSecp256k1,
-            SigningKeyEnum::Rsa(_) => ProtoKeyType::Rsa,
-        }
-    }
-
-    /// Signs `msg` and returns raw signature bytes matching the server-side verification.
-    pub fn sign(&self, msg: &[u8]) -> Vec<u8> {
-        match self {
-            SigningKeyEnum::Ed25519(k) => {
-                use ed25519_dalek::Signer as _;
-                k.sign(msg).to_bytes().to_vec()
-            }
-            SigningKeyEnum::EcdsaSecp256k1(k) => {
-                use k256::ecdsa::signature::Signer as _;
-                let sig: k256::ecdsa::Signature = k.sign(msg);
-                sig.to_bytes().to_vec()
-            }
-            SigningKeyEnum::Rsa(k) => {
-                use rsa::signature::RandomizedSigner as _;
-                let signing_key = rsa::pss::BlindedSigningKey::<sha2::Sha256>::new(k.clone());
-                // Use rand_core OsRng from the rsa crate's re-exported rand_core (0.6.x),
-                // which is the version rsa's signature API expects.
-                let sig = signing_key.sign_with_rng(&mut rsa::rand_core::OsRng, msg);
-                use rsa::signature::SignatureEncoding as _;
-                sig.to_vec()
-            }
-        }
-    }
-}
-
-statemachine! {
-    name: UserAgent,
-    custom_error: false,
-    transitions: {
-        *Init + SentAuthChallengeRequest = WaitingForServerAuth,
-        WaitingForServerAuth + ReceivedAuthChallenge = WaitingForAuthOk,
-        WaitingForServerAuth + ReceivedAuthOk = Authenticated,
-        WaitingForAuthOk + ReceivedAuthOk = Authenticated,
-    }
-}
-
-pub struct DummyContext;
-impl UserAgentStateMachineContext for DummyContext {}
-
-#[derive(Debug, thiserror::Error)]
-pub enum InboundError {
-    #[error("Invalid user agent response")]
-    InvalidResponse,
-    #[error("Expected response payload")]
-    MissingResponsePayload,
-    #[error("Unexpected response payload")]
-    UnexpectedResponsePayload,
-    #[error("Invalid state for auth challenge")]
-    InvalidStateForAuthChallenge,
-    #[error("Invalid state for auth ok")]
-    InvalidStateForAuthOk,
-    #[error("State machine error")]
-    StateTransitionFailed,
-    #[error("Transport send failed")]
-    TransportSendFailed,
-}
-
-pub struct UserAgentActor<Transport>
-where
-    Transport: Bi<UserAgentResponse, UserAgentRequest>,
-{
-    key: SigningKeyEnum,
-    bootstrap_token: Option<String>,
-    state: UserAgentStateMachine<DummyContext>,
-    transport: Transport,
-}
-
-impl<Transport> UserAgentActor<Transport>
-where
-    Transport: Bi<UserAgentResponse, UserAgentRequest>,
-{
-    pub fn new(key: SigningKeyEnum, bootstrap_token: Option<String>, transport: Transport) -> Self {
-        Self {
-            key,
-            bootstrap_token,
-            state: UserAgentStateMachine::new(DummyContext),
-            transport,
-        }
-    }
-
-    fn transition(&mut self, event: UserAgentEvents) -> Result<(), InboundError> {
-        self.state.process_event(event).map_err(|e| {
-            error!(?e, "useragent state transition failed");
-            InboundError::StateTransitionFailed
-        })?;
-        Ok(())
-    }
-
-    async fn send_auth_challenge_request(&mut self) -> Result<(), InboundError> {
-        let req = AuthChallengeRequest {
-            pubkey: self.key.pubkey_bytes(),
-            bootstrap_token: self.bootstrap_token.take(),
-            key_type: self.key.proto_key_type().into(),
-        };
-
-        self.transition(UserAgentEvents::SentAuthChallengeRequest)?;
-
-        self.transport
-            .send(UserAgentRequest {
-                payload: Some(UserAgentRequestPayload::AuthChallengeRequest(req)),
-            })
-            .await
-            .map_err(|_| InboundError::TransportSendFailed)?;
-
-        info!(actor = "useragent", "auth.request.sent");
-        Ok(())
-    }
-
-    async fn handle_auth_challenge(
-        &mut self,
-        challenge: arbiter_proto::proto::user_agent::AuthChallenge,
-    ) -> Result<(), InboundError> {
-        self.transition(UserAgentEvents::ReceivedAuthChallenge)?;
-
-        let formatted = format_challenge(challenge.nonce, &challenge.pubkey);
-        let signature_bytes = self.key.sign(&formatted);
-        let solution = AuthChallengeSolution {
-            signature: signature_bytes,
-        };
-
-        self.transport
-            .send(UserAgentRequest {
-                payload: Some(UserAgentRequestPayload::AuthChallengeSolution(solution)),
-            })
-            .await
-            .map_err(|_| InboundError::TransportSendFailed)?;
-
-        info!(actor = "useragent", "auth.solution.sent");
-        Ok(())
-    }
-
-    fn handle_auth_ok(&mut self, _ok: AuthOk) -> Result<(), InboundError> {
-        self.transition(UserAgentEvents::ReceivedAuthOk)?;
-        info!(actor = "useragent", "auth.ok");
-        Ok(())
-    }
-
-    pub async fn process_inbound_transport(
-        &mut self,
-        inbound: UserAgentResponse,
-    ) -> Result<(), InboundError> {
-        let payload = inbound
-            .payload
-            .ok_or(InboundError::MissingResponsePayload)?;
-
-        match payload {
-            UserAgentResponsePayload::AuthChallenge(challenge) => {
-                self.handle_auth_challenge(challenge).await
-            }
-            UserAgentResponsePayload::AuthOk(ok) => self.handle_auth_ok(ok),
-            _ => Err(InboundError::UnexpectedResponsePayload),
-        }
-    }
-}
-
-impl<Transport> Actor for UserAgentActor<Transport>
-where
-    Transport: Bi<UserAgentResponse, UserAgentRequest>,
-{
-    type Args = Self;
-
-    type Error = ();
-
-    async fn on_start(
-        mut args: Self::Args,
-        _actor_ref: ActorRef<Self>,
-    ) -> Result<Self, Self::Error> {
-        if let Err(err) = args.send_auth_challenge_request().await {
-            error!(?err, actor = "useragent", "auth.start.failed");
-            return Err(());
-        }
-        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;
-                }
-                inbound = self.transport.recv() => {
-                    match inbound {
-                        Some(inbound) => {
-                            if let Err(err) = self.process_inbound_transport(inbound).await {
-                                error!(?err, actor = "useragent", "transport.inbound.failed");
-                                return Some(kameo::mailbox::Signal::Stop);
-                            }
-                        }
-                        None => {
-                            info!(actor = "useragent", "transport.closed");
-                            return Some(kameo::mailbox::Signal::Stop);
-                        }
-                    }
-                }
-            }
-        }
-    }
-}
-
-mod grpc;
-pub use grpc::{ConnectError, connect_grpc};

server/crates/arbiter-useragent/tests/auth.rs

@@ -1,146 +0,0 @@
-use arbiter_proto::{
-    format_challenge,
-    proto::user_agent::{
-        AuthChallenge, AuthOk, UserAgentRequest, UserAgentResponse,
-        user_agent_request::Payload as UserAgentRequestPayload,
-        user_agent_response::Payload as UserAgentResponsePayload,
-    },
-    transport::Bi,
-};
-use arbiter_useragent::{SigningKeyEnum, UserAgentActor};
-use async_trait::async_trait;
-use ed25519_dalek::SigningKey;
-use kameo::actor::Spawn;
-use tokio::sync::mpsc;
-use tokio::time::{Duration, timeout};
-
-struct TestTransport {
-    inbound_rx: mpsc::Receiver<UserAgentResponse>,
-    outbound_tx: mpsc::Sender<UserAgentRequest>,
-}
-
-#[async_trait]
-impl Bi<UserAgentResponse, UserAgentRequest> for TestTransport {
-    async fn send(
-        &mut self,
-        item: UserAgentRequest,
-    ) -> Result<(), arbiter_proto::transport::Error> {
-        self.outbound_tx
-            .send(item)
-            .await
-            .map_err(|_| arbiter_proto::transport::Error::ChannelClosed)
-    }
-
-    async fn recv(&mut self) -> Option<UserAgentResponse> {
-        self.inbound_rx.recv().await
-    }
-}
-
-fn make_transport() -> (
-    TestTransport,
-    mpsc::Sender<UserAgentResponse>,
-    mpsc::Receiver<UserAgentRequest>,
-) {
-    let (inbound_tx, inbound_rx) = mpsc::channel(8);
-    let (outbound_tx, outbound_rx) = mpsc::channel(8);
-    (
-        TestTransport {
-            inbound_rx,
-            outbound_tx,
-        },
-        inbound_tx,
-        outbound_rx,
-    )
-}
-
-fn test_key() -> SigningKeyEnum {
-    SigningKeyEnum::Ed25519(SigningKey::from_bytes(&[7u8; 32]))
-}
-
-#[tokio::test]
-async fn sends_auth_request_on_start_with_bootstrap_token() {
-    let key = test_key();
-    let pubkey = key.pubkey_bytes();
-    let bootstrap_token = Some("bootstrap-123".to_string());
-    let (transport, inbound_tx, mut outbound_rx) = make_transport();
-
-    let actor = UserAgentActor::spawn(UserAgentActor::new(key, bootstrap_token.clone(), transport));
-
-    let outbound = timeout(Duration::from_secs(1), outbound_rx.recv())
-        .await
-        .expect("timed out waiting for auth request")
-        .expect("channel closed before auth request");
-
-    let UserAgentRequest {
-        payload: Some(UserAgentRequestPayload::AuthChallengeRequest(req)),
-    } = outbound
-    else {
-        panic!("expected auth challenge request");
-    };
-
-    assert_eq!(req.pubkey, pubkey);
-    assert_eq!(req.bootstrap_token, bootstrap_token);
-
-    drop(inbound_tx);
-    drop(actor);
-}
-
-#[tokio::test]
-async fn challenge_flow_sends_solution_from_transport_inbound() {
-    let key = test_key();
-    let pubkey_bytes = key.pubkey_bytes();
-    let (transport, inbound_tx, mut outbound_rx) = make_transport();
-
-    let actor = UserAgentActor::spawn(UserAgentActor::new(key, None, transport));
-
-    let _initial_auth_request = timeout(Duration::from_secs(1), outbound_rx.recv())
-        .await
-        .expect("timed out waiting for initial auth request")
-        .expect("missing initial auth request");
-
-    let challenge = AuthChallenge {
-        pubkey: pubkey_bytes.clone(),
-        nonce: 42,
-    };
-    inbound_tx
-        .send(UserAgentResponse {
-            payload: Some(UserAgentResponsePayload::AuthChallenge(challenge.clone())),
-        })
-        .await
-        .unwrap();
-
-    let outbound = timeout(Duration::from_secs(1), outbound_rx.recv())
-        .await
-        .expect("timed out waiting for challenge solution")
-        .expect("missing challenge solution");
-
-    let UserAgentRequest {
-        payload: Some(UserAgentRequestPayload::AuthChallengeSolution(solution)),
-    } = outbound
-    else {
-        panic!("expected auth challenge solution");
-    };
-
-    // Verify the signature using the Ed25519 verifying key
-    let formatted = format_challenge(challenge.nonce, &challenge.pubkey);
-    let raw_key = SigningKey::from_bytes(&[7u8; 32]);
-    let sig: ed25519_dalek::Signature = solution
-        .signature
-        .as_slice()
-        .try_into()
-        .expect("signature bytes length");
-    raw_key
-        .verifying_key()
-        .verify_strict(&formatted, &sig)
-        .expect("solution signature should verify");
-
-    inbound_tx
-        .send(UserAgentResponse {
-            payload: Some(UserAgentResponsePayload::AuthOk(AuthOk {})),
-        })
-        .await
-        .unwrap();
-
-    drop(inbound_tx);
-    drop(actor);
-}

server/rules/safecell/new-inline.yaml

@@ -0,0 +1,10 @@
+id: safecell-new-inline
+language: Rust
+rule:
+  pattern: $CELL.write_inline(|$W| $BODY);
+  follows:
+    pattern: let mut $CELL = SafeCell::new($INIT);
+fix: 
+  template: let mut $CELL = SafeCell::new_inline(|$W| $BODY);
+  expandStart:
+    pattern: let mut $CELL = SafeCell::new($INIT)

server/rules/safecell/read-inline.yaml

@@ -0,0 +1,17 @@
+id: safecell-read-inline
+language: Rust
+rule:
+  pattern: 
+    context: |
+      {
+          let $READ = $CELL.read();
+          $$$BODY
+      }
+    selector: block
+  inside:
+    kind: block
+fix: 
+  template: | 
+    $CELL.read_inline(|$READ| { 
+      $$$BODY 
+    });

server/rules/safecell/write-inline.yaml

@@ -0,0 +1,13 @@
+id: safecell-write-inline
+language: Rust
+rule:
+  pattern: |
+    {
+        let mut $WRITE = $CELL.write();
+        $$$BODY
+    }
+fix: 
+  template: | 
+    $CELL.write_inline(|$WRITE| { 
+      $$$BODY 
+    });

server/sgconfig.yml

@@ -0,0 +1,2 @@
+ruleDirs:
+- ./rules

useragent/.dart_tool/extension_discovery/README.md

@@ -1,31 +0,0 @@
-Extension Discovery Cache
-=========================
-
-This folder is used by `package:extension_discovery` to cache lists of
-packages that contains extensions for other packages.
-
-DO NOT USE THIS FOLDER
-----------------------
-
- * Do not read (or rely) the contents of this folder.
- * Do write to this folder.
-
-If you're interested in the lists of extensions stored in this folder use the
-API offered by package `extension_discovery` to get this information.
-
-If this package doesn't work for your use-case, then don't try to read the
-contents of this folder. It may change, and will not remain stable.
-
-Use package `extension_discovery`
----------------------------------
-
-If you want to access information from this folder.
-
-Feel free to delete this folder
--------------------------------
-
-Files in this folder act as a cache, and the cache is discarded if the files
-are older than the modification time of `.dart_tool/package_config.json`.
-
-Hence, it should never be necessary to clear this cache manually, if you find a
-need to do please file a bug.

useragent/.dart_tool/extension_discovery/vs_code.json

@@ -1 +0,0 @@
-{"version":2,"entries":[{"package":"arbiter","rootUri":"../","packageUri":"lib/"}]}

useragent/.dart_tool/package_config.json

@@ -1,172 +0,0 @@
-{
-  "configVersion": 2,
-  "packages": [
-    {
-      "name": "async",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/async-2.13.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "boolean_selector",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/boolean_selector-2.1.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "characters",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/characters-1.4.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "clock",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/clock-1.1.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "collection",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/collection-1.19.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "fake_async",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/fake_async-1.3.3",
-      "packageUri": "lib/",
-      "languageVersion": "3.3"
-    },
-    {
-      "name": "flutter",
-      "rootUri": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable/packages/flutter",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "flutter_lints",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/flutter_lints-6.0.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "flutter_test",
-      "rootUri": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable/packages/flutter_test",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "leak_tracker",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/leak_tracker-11.0.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.2"
-    },
-    {
-      "name": "leak_tracker_flutter_testing",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/leak_tracker_flutter_testing-3.0.10",
-      "packageUri": "lib/",
-      "languageVersion": "3.2"
-    },
-    {
-      "name": "leak_tracker_testing",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/leak_tracker_testing-3.0.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.2"
-    },
-    {
-      "name": "lints",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/lints-6.1.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "matcher",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/matcher-0.12.17",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "material_color_utilities",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/material_color_utilities-0.11.1",
-      "packageUri": "lib/",
-      "languageVersion": "2.17"
-    },
-    {
-      "name": "meta",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/meta-1.17.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.5"
-    },
-    {
-      "name": "path",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/path-1.9.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "sky_engine",
-      "rootUri": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable/bin/cache/pkg/sky_engine",
-      "packageUri": "lib/",
-      "languageVersion": "3.8"
-    },
-    {
-      "name": "source_span",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/source_span-1.10.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "stack_trace",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/stack_trace-1.12.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.4"
-    },
-    {
-      "name": "stream_channel",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/stream_channel-2.1.4",
-      "packageUri": "lib/",
-      "languageVersion": "3.3"
-    },
-    {
-      "name": "string_scanner",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/string_scanner-1.4.1",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "term_glyph",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/term_glyph-1.2.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "test_api",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/test_api-0.7.7",
-      "packageUri": "lib/",
-      "languageVersion": "3.5"
-    },
-    {
-      "name": "vector_math",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/vector_math-2.2.0",
-      "packageUri": "lib/",
-      "languageVersion": "3.1"
-    },
-    {
-      "name": "vm_service",
-      "rootUri": "file:///Users/kaska/.pub-cache/hosted/pub.dev/vm_service-15.0.2",
-      "packageUri": "lib/",
-      "languageVersion": "3.5"
-    },
-    {
-      "name": "arbiter",
-      "rootUri": "../",
-      "packageUri": "lib/",
-      "languageVersion": "3.10"
-    }
-  ],
-  "generator": "pub",
-  "generatorVersion": "3.10.8",
-  "flutterRoot": "file:///Users/kaska/.local/share/mise/installs/flutter/3.38.9-stable",
-  "flutterVersion": "3.38.9",
-  "pubCache": "file:///Users/kaska/.pub-cache"
-}

useragent/.dart_tool/package_graph.json

@@ -1,224 +0,0 @@
-{
-  "roots": [
-    "arbiter"
-  ],
-  "packages": [
-    {
-      "name": "arbiter",
-      "version": "0.1.0",
-      "dependencies": [
-        "flutter"
-      ],
-      "devDependencies": [
-        "flutter_lints",
-        "flutter_test"
-      ]
-    },
-    {
-      "name": "flutter_lints",
-      "version": "6.0.0",
-      "dependencies": [
-        "lints"
-      ]
-    },
-    {
-      "name": "flutter_test",
-      "version": "0.0.0",
-      "dependencies": [
-        "clock",
-        "collection",
-        "fake_async",
-        "flutter",
-        "leak_tracker_flutter_testing",
-        "matcher",
-        "meta",
-        "path",
-        "stack_trace",
-        "stream_channel",
-        "test_api",
-        "vector_math"
-      ]
-    },
-    {
-      "name": "flutter",
-      "version": "0.0.0",
-      "dependencies": [
-        "characters",
-        "collection",
-        "material_color_utilities",
-        "meta",
-        "sky_engine",
-        "vector_math"
-      ]
-    },
-    {
-      "name": "lints",
-      "version": "6.1.0",
-      "dependencies": []
-    },
-    {
-      "name": "stream_channel",
-      "version": "2.1.4",
-      "dependencies": [
-        "async"
-      ]
-    },
-    {
-      "name": "meta",
-      "version": "1.17.0",
-      "dependencies": []
-    },
-    {
-      "name": "collection",
-      "version": "1.19.1",
-      "dependencies": []
-    },
-    {
-      "name": "leak_tracker_flutter_testing",
-      "version": "3.0.10",
-      "dependencies": [
-        "flutter",
-        "leak_tracker",
-        "leak_tracker_testing",
-        "matcher",
-        "meta"
-      ]
-    },
-    {
-      "name": "vector_math",
-      "version": "2.2.0",
-      "dependencies": []
-    },
-    {
-      "name": "stack_trace",
-      "version": "1.12.1",
-      "dependencies": [
-        "path"
-      ]
-    },
-    {
-      "name": "clock",
-      "version": "1.1.2",
-      "dependencies": []
-    },
-    {
-      "name": "fake_async",
-      "version": "1.3.3",
-      "dependencies": [
-        "clock",
-        "collection"
-      ]
-    },
-    {
-      "name": "path",
-      "version": "1.9.1",
-      "dependencies": []
-    },
-    {
-      "name": "matcher",
-      "version": "0.12.17",
-      "dependencies": [
-        "async",
-        "meta",
-        "stack_trace",
-        "term_glyph",
-        "test_api"
-      ]
-    },
-    {
-      "name": "test_api",
-      "version": "0.7.7",
-      "dependencies": [
-        "async",
-        "boolean_selector",
-        "collection",
-        "meta",
-        "source_span",
-        "stack_trace",
-        "stream_channel",
-        "string_scanner",
-        "term_glyph"
-      ]
-    },
-    {
-      "name": "sky_engine",
-      "version": "0.0.0",
-      "dependencies": []
-    },
-    {
-      "name": "material_color_utilities",
-      "version": "0.11.1",
-      "dependencies": [
-        "collection"
-      ]
-    },
-    {
-      "name": "characters",
-      "version": "1.4.0",
-      "dependencies": []
-    },
-    {
-      "name": "async",
-      "version": "2.13.0",
-      "dependencies": [
-        "collection",
-        "meta"
-      ]
-    },
-    {
-      "name": "leak_tracker_testing",
-      "version": "3.0.2",
-      "dependencies": [
-        "leak_tracker",
-        "matcher",
-        "meta"
-      ]
-    },
-    {
-      "name": "leak_tracker",
-      "version": "11.0.2",
-      "dependencies": [
-        "clock",
-        "collection",
-        "meta",
-        "path",
-        "vm_service"
-      ]
-    },
-    {
-      "name": "term_glyph",
-      "version": "1.2.2",
-      "dependencies": []
-    },
-    {
-      "name": "string_scanner",
-      "version": "1.4.1",
-      "dependencies": [
-        "source_span"
-      ]
-    },
-    {
-      "name": "source_span",
-      "version": "1.10.2",
-      "dependencies": [
-        "collection",
-        "path",
-        "term_glyph"
-      ]
-    },
-    {
-      "name": "boolean_selector",
-      "version": "2.1.2",
-      "dependencies": [
-        "source_span",
-        "string_scanner"
-      ]
-    },
-    {
-      "name": "vm_service",
-      "version": "15.0.2",
-      "dependencies": []
-    }
-  ],
-  "configVersion": 1
-}

useragent/.dart_tool/version

@@ -1 +0,0 @@
-3.38.9

useragent/README.md

@@ -1,4 +1,4 @@
-# app
+# useragent
 
 A new Flutter project.
 

useragent/android/.gitignore

@@ -0,0 +1,14 @@
+gradle-wrapper.jar
+/.gradle
+/captures/
+/gradlew
+/gradlew.bat
+/local.properties
+GeneratedPluginRegistrant.java
+.cxx/
+
+# Remember to never publicly share your keystore.
+# See https://flutter.dev/to/reference-keystore
+key.properties
+**/*.keystore
+**/*.jks

useragent/android/app/build.gradle.kts

@@ -0,0 +1,44 @@
+plugins {
+    id("com.android.application")
+    id("kotlin-android")
+    // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins.
+    id("dev.flutter.flutter-gradle-plugin")
+}
+
+android {
+    namespace = "com.example.useragent"
+    compileSdk = flutter.compileSdkVersion
+    ndkVersion = flutter.ndkVersion
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+
+    kotlinOptions {
+        jvmTarget = JavaVersion.VERSION_17.toString()
+    }
+
+    defaultConfig {
+        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
+        applicationId = "com.example.useragent"
+        // You can update the following values to match your application needs.
+        // For more information, see: https://flutter.dev/to/review-gradle-config.
+        minSdk = flutter.minSdkVersion
+        targetSdk = flutter.targetSdkVersion
+        versionCode = flutter.versionCode
+        versionName = flutter.versionName
+    }
+
+    buildTypes {
+        release {
+            // TODO: Add your own signing config for the release build.
+            // Signing with the debug keys for now, so `flutter run --release` works.
+            signingConfig = signingConfigs.getByName("debug")
+        }
+    }
+}
+
+flutter {
+    source = "../.."
+}

useragent/android/app/src/debug/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- The INTERNET permission is required for development. Specifically,
+         the Flutter tool needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>

useragent/android/app/src/main/AndroidManifest.xml

@@ -0,0 +1,45 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <application
+        android:label="useragent"
+        android:name="${applicationName}"
+        android:icon="@mipmap/ic_launcher">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:launchMode="singleTop"
+            android:taskAffinity=""
+            android:theme="@style/LaunchTheme"
+            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
+            android:hardwareAccelerated="true"
+            android:windowSoftInputMode="adjustResize">
+            <!-- Specifies an Android theme to apply to this Activity as soon as
+                 the Android process has started. This theme is visible to the user
+                 while the Flutter UI initializes. After that, this theme continues
+                 to determine the Window background behind the Flutter UI. -->
+            <meta-data
+              android:name="io.flutter.embedding.android.NormalTheme"
+              android:resource="@style/NormalTheme"
+              />
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+        </activity>
+        <!-- Don't delete the meta-data below.
+             This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
+        <meta-data
+            android:name="flutterEmbedding"
+            android:value="2" />
+    </application>
+    <!-- Required to query activities that can process text, see:
+         https://developer.android.com/training/package-visibility and
+         https://developer.android.com/reference/android/content/Intent#ACTION_PROCESS_TEXT.
+
+         In particular, this is used by the Flutter engine in io.flutter.plugin.text.ProcessTextPlugin. -->
+    <queries>
+        <intent>
+            <action android:name="android.intent.action.PROCESS_TEXT"/>
+            <data android:mimeType="text/plain"/>
+        </intent>
+    </queries>
+</manifest>

useragent/android/app/src/main/kotlin/com/example/useragent/MainActivity.kt

@@ -0,0 +1,5 @@
+package com.example.useragent
+
+import io.flutter.embedding.android.FlutterActivity
+
+class MainActivity : FlutterActivity()

useragent/android/app/src/main/res/drawable-v21/launch_background.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Modify this file to customize your launch splash screen -->
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="?android:colorBackground" />
+
+    <!-- You can insert your own image assets here -->
+    <!-- <item>
+        <bitmap
+            android:gravity="center"
+            android:src="@mipmap/launch_image" />
+    </item> -->
+</layer-list>

useragent/android/app/src/main/res/drawable/launch_background.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Modify this file to customize your launch splash screen -->
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="@android:color/white" />
+
+    <!-- You can insert your own image assets here -->
+    <!-- <item>
+        <bitmap
+            android:gravity="center"
+            android:src="@mipmap/launch_image" />
+    </item> -->
+</layer-list>