fix(agent): emit MCP progress for completed steps

[HsiangNianian]

What & why

The agent tool documents stream: true as sending progress for completed steps, but the MCP handler never passed its progress callback into the agent pipeline. Clients that supplied a progress token therefore received only the final result.

Fixes #248.

Changes

• Forward the MCP progress callback into agent only when streaming is enabled.
• Emit ordered updates from the existing plan, search, fetch, extract, and synthesize step boundaries.
• Keep the final agent result intact if a client disconnects while a notification is sent.
• Cover both the agent callback contract and the SDK transport path.

Testing

• npm run test:unit — 589 files, 7,333 tests passed.
• npx vitest run tests/integration/agent.test.ts tests/unit/agent/executor.test.ts — 28 tests passed.
• npx vitest run tests/unit/server/schema-registration.test.ts — 7 tests passed.
• npm run lint
• npm run build
• Added regression coverage for the new behavior.
• npm test — passed in PR CI; one local REST find_similar cold-start timeout while loading fastembed did not reproduce on the clean runner.

Checklist

• Follows Conventional Commits.
• Focused change (no unrelated refactoring).
• I have read CONTRIBUTING.md and agree to its contribution terms.

[coderabbitai]

📝 Walkthrough

Walkthrough

Agent pipeline phases and search/fetch execution steps now emit progress callbacks. The MCP server forwards callbacks for streaming agent requests, while callback failures are suppressed and final responses remain successful.

Changes

Agent progress reporting

Layer / File(s)	Summary
Pipeline and execution progress reporting src/agent/executor.ts, src/agent/pipeline.ts	Search, fetch, plan, extraction, and synthesis steps now invoke progress callbacks. Callback failures are logged without aborting execution.
Streaming callback propagation src/server.ts, src/tools/agent.ts	The MCP agent handler forwards progress callbacks and enables them only when streaming is requested.
Progress behavior validation tests/integration/agent.test.ts, tests/unit/server/schema-registration.test.ts	Tests verify ordered progress updates, step-detail mapping, disabled streaming behavior, callback failures, and successful responses.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers: knockoutez

Sequence Diagram(s)

sequenceDiagram
  participant MCPClient
  participant server
  participant handleAgent
  participant runAgentPipeline
  participant executeAgentPlan
  MCPClient->>server: call agent with stream true
  server->>handleAgent: forward onProgress
  handleAgent->>runAgentPipeline: pass streaming callback
  runAgentPipeline->>executeAgentPlan: pass reportStep
  runAgentPipeline-->>MCPClient: plan progress
  executeAgentPlan-->>MCPClient: search and fetch progress
  runAgentPipeline-->>MCPClient: extraction and synthesis progress
  runAgentPipeline-->>MCPClient: final agent result

Loading

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The PR emits progress notifications only for stream=true and covers the documented agent step boundaries, satisfying #248.
Out of Scope Changes check	✅ Passed	The code and tests all support the agent progress-notification fix; no unrelated changes stand out.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: emitting MCP progress updates for the agent tool at step boundaries.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[KnockOutEZ]

Hi @HsiangNianian — thank you for this PR, and I'm sorry it's been sitting here without a proper review.

I've been heads-down building some pretty big features and improvements for wigolo, and as a solo dev, shipping that while also reviewing and maintaining every issue and PR has been genuinely hard. This one isn't forgotten — it just hasn't had the attention it deserves yet.

I'd really appreciate your patience here. I'm going to work through the open PRs and issues properly over the next few weeks (sooner if I can free up), and I'll follow up right here.

In the meantime, the wigolo Discord is open if you'd like to follow what's being built, ask questions, or nudge me directly: https://discord.gg/BkUUgz2bNF

Thanks again for contributing, and for understanding — it genuinely means a lot. 🙏

[HsiangNianian]

Hi @HsiangNianian — thank you for this PR, and I'm sorry it's been sitting here without a proper review.

I've been heads-down building some pretty big features and improvements for wigolo, and as a solo dev, shipping that while also reviewing and maintaining every issue and PR has been genuinely hard. This one isn't forgotten — it just hasn't had the attention it deserves yet.

I'd really appreciate your patience here. I'm going to work through the open PRs and issues properly over the next few weeks (sooner if I can free up), and I'll follow up right here.

In the meantime, the wigolo Discord is open if you'd like to follow what's being built, ask questions, or nudge me directly: https://discord.gg/BkUUgz2bNF

Thanks again for contributing, and for understanding — it genuinely means a lot. 🙏

No worries at all, and thanks for the heads-up. Totally understand — take your time. I’m glad to hear the PR is still on your radar. Happy to help with anything needed when you get around to reviewing it. Good luck with the big wigolo updates!