fix(mcp): serve streamable HTTP GET

[JustAGhosT]

Summary

• Route GET /mcp through the existing bearer-protected MCP handler.
• Preserve current POST /mcp behavior while allowing Claude Code to open the streamable HTTP SSE channel.

Verification

• pnpm --dir backend typecheck
• pnpm --dir backend test
• pnpm --dir backend build
• Local smoke: GET /mcp with bearer + Accept: text/event-stream returns 200 text/event-stream.

Summary by CodeRabbit

• Bug Fixes
  • Enhanced error handling for request processing with improved logging and appropriate error responses.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: e7e272fe-432c-4ecb-b0c2-2eb900989629

📥 Commits

Reviewing files that changed from the base of the PR and between 1ce82da and 4dd2ce8.

📒 Files selected for processing (1)

• backend/src/mcp/server.ts

---

📝 Walkthrough

Walkthrough

Refactored MCP HTTP handling by extracting request-processing logic into a shared handleMcpHttpRequest helper function and wiring both POST / and GET / routes to call it, with the helper receiving req.body for POST requests and undefined for GET requests.

Changes

MCP HTTP Request Handler Extraction

Layer / File(s)	Summary
HTTP request handler extraction and routing backend/src/mcp/server.ts	New handleMcpHttpRequest helper function encapsulates transport creation, server connection, and request delegation; both POST / and GET / routes call this helper with body data passed conditionally, and error handling logs unhandled errors and returns 500 JSON only if headers have not been sent.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related PRs

• phoenixvc/baton#48: Both PRs adjust MCP HTTP handling around StreamableHTTPServerTransport; this PR routes GET/POST / through the transport handler while the related PR updates orgClient to send matching Accept headers that the transport expects.

Poem

🐰 A helper born from duplication's sting,
Routes now dance to the same shared thing,
POST and GET in harmony agree,
One transport handler, clean and spry! ✨

🚥 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
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The PR title accurately and concisely describes the main change: fixing the MCP server to serve streamable HTTP GET requests, which directly matches the refactoring that enables GET /mcp routing through the bearer-protected handler.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/mcp-get-stream

---

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 and usage tips.}