PLUGIN: Claude OAuth — complete subscription connection

[sunrisegm]

Summary

Add a complete Claude subscription OAuth provider plugin, based on clean upstream commit 9a8fde2 with no unrelated local changes.

• Browser authorization using host-owned state/PKCE validation and a localhost callback.
• Profile lookup, host-owned private credential persistence, refresh-token rotation/coalescing, and one pre-output HTTP 401 retry.
• Paginated upstream model discovery with capability metadata.
• Anthropic Messages streaming with images, tool calls, ordered signed/redacted thinking replay, usage, cancellation, and strict truncated-stream handling.
• Explicit account states for authorization failures and HTTP 429 cooldown.
• Bundling, documentation, 32 unit tests, an actual sandboxed-worker integration test, and a dedicated Deno CI job pinned to the host runtime version.

Structure

.github/workflows/ci.yml          # Run Claude plugin checks on Deno 2.9.6
server/
├── plugins/build-in/claude-auth/ # OAuth, accounts, models, Messages adapter, tests, documentation
└── src/plugin/
    ├── builtin.rs               # Bundle the plugin in release builds
    └── worker.rs                # Exclude auxiliary fetches from model-call recording

The host change prevents an auxiliary OAuth refresh from claiming the model-call recorder and persisting token request/response bodies with detailed logging enabled. Only inference streams now claim that recorder; a Rust regression test covers this behavior. No frontend, database schema, or provider-independent history changes are included.

Verification completed locally

Linux, Rust 1.98.1, in isolated Docker build environments using this checkout:

• cargo fmt --all -- --check: passed.
• cargo clippy --locked --workspace --all-targets -- -D warnings: passed.
• cargo test --locked --workspace --all-targets -- --test-threads=2: 306 passed, 0 failed. Includes 20 plugin-host tests and the credential-recording regression.
• cargo build --locked --offline --workspace: passed, server and desktop debug binaries linked.

Deno 2.9.6, matching server/src/plugin/asset.rs:

• Type check, lint, and formatting: passed.
• Unit tests: 32 passed, 0 failed.
• deno task test:host: 1 passed. Starts the actual SDK worker with host sandbox restrictions and drives OAuth completion, profile/model lookup, automatic refresh, streamed events, resource patches, and stream cleanup through the JSON protocol. Upstream responses are mocked.
• Plugin descriptor loading under host sandbox flags: passed.

Frontend, Node 22.23.2:

• npm run check: passed (both TypeScript checks and Vite production build; 1,849 modules transformed).
• Existing dependencies were mounted read-only. A fresh npm ci was attempted but hit a registry download timeout; a fresh dependency install is therefore not verified.

Live Claude verification — 2026-09-30

A temporary, memory-only harness invoked the actual plugin modules with explicit browser consent:

• Browser callback and state validation: passed.
• Authorization-code exchange and profile lookup: passed.
• Refresh-token rotation: passed.
• Model discovery: 13 models returned.
• A short streamed text request to claude-haiku-4-5-20251001: passed.

The requested scopes were user:profile user:inference. This live request succeeded without impersonating Claude Code, injecting an official-client system identity, or forging a CLI version. Tokens remained in process memory and were not written to files, Git, or the running application's profile.

Remaining coverage boundaries

• Live testing covered one account and one model, not every returned model or account type.
• Tool calling, thinking replay, rate-limit handling, and error paths were exercised with mocks, not live calls.
• Full graphical desktop sign-in, persistence/restart recovery, macOS/Windows builds, and release installers were not tested locally.
• Upstream GitHub Actions require maintainer approval for this fork PR; local results are not presented as completed hosted CI.

Status

The plugin is a complete Claude subscription connection: sign-in, token refresh, model discovery, and streamed inference. Anthropic's authentication policy still governs how subscription credentials may be used.

Use a build containing the host recording fix rather than installing this plugin into an unpatched release. See server/plugins/build-in/claude-auth/README.md for installation, lifecycle, storage/crash limitations, and protocol sources.