[qduc]

Summary

Part B of #40. When AGENT_HARNESS_TOOL_LOOP=true (off by default), the streaming tool loop runs on @qduc/agent-core. The PR also adds end-to-end replay tests that run both tool loops against recorded provider traffic, with no real API calls. While building the tests I found and fixed a real bug in the upstream logging tee.

Changes

Harness loop (212cc13)

• backend/src/lib/harness/harnessToolsStreaming.ts runs the flagged loop. openaiProxy.js routes to it when the flag is on.
• providerModel.ts retries a reasoning-only response twice, then emits the existing incomplete-reasoning warning.

Provider replay e2e (50542e5, 9e73ce2)

• integration/providerReplay.test.js replays sanitized real recordings from Term2 for Chat Completions, Responses, Anthropic and Gemini. Each one goes through the real route, adapters, tools and persistence, once per loop.
• Parallel tool calls use synthetic fixtures derived from those recordings. Sources are listed in fixtures/PROVENANCE.md.
• integration/syntheticFixtureOracle.test.js serves every fixture to the official openai, @anthropic-ai/sdk and @google/genai SDKs:
  • real recordings must parse to their recorded call (calibration);
  • synthetic fixtures must parse to both calls.
• The replay server can stall or drop a turn mid-stream. This drives the Stop and upstream-drop scenarios in both loops.

Bug fix (92c2016)

• upstreamLogger.js: pipe() doesn't forward errors from the source stream. When a provider connection dropped mid-answer, the client waited for the 30s idle timeout. The fix destroys the passthrough with the source error, so the drop is now detected in about 100ms.
• toModelFailure now reads error messages by duck typing, because errors from another realm fail instanceof Error.

Install @qduc/agent-core from npm (2b0cfff)

• 0.2.0-alpha.1 is published. Backend and electron pin that exact version; both lockfiles resolve from registry.npmjs.org.
• The registry tarball has the same sha512 integrity as the tarball previously vendored here (packed by qduc/agent-runtime 3e322ba), so the installed code is identical.
• backend/vendor/ and the COPY vendor lines in both Dockerfiles are gone.

Verification

• Backend: npm run lint and npm run typecheck are clean. The full jest suite passes: 1352 passed, 3 skipped, 15 todo.
• npm run test:provider-replay: 60/60.
• A clean npm ci in electron installs 0.2.0-alpha.1 from npm.
• Mutation checks:
  • the oracle rejects a reused Anthropic block index and a missing Chat id;
  • the drop test fails with the tee fix reverted.

Known limits

• The parallel fixtures are a best guess at each provider's wire format. They are valid for the vendors' own parsers, but they aren't captures. Replace each one with a real capture when one is available.
• The harness loop doesn't send previous_response_id and ignores provider_stream:false.
• Streamed tool_output is a string in the harness loop and an object in the legacy loop.

Related

• qduc/agent-runtime and qduc/term2 PRs from ccr-c2e20a05-677q07. term2 still installs a vendored tarball and needs the same switch to npm.

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