fix(ai): Accept header for docs-tools MCP endpoint

[mantrakp04]

Summary

Production requests to https://mcp.stack-auth.com/api/internal/docs-tools were returning 406 with Not Acceptable: Client must accept both application/json and text/event-stream because postDocsToolAction only set Content-Type.

Change

Set Accept: application/json, text/event-stream on the fetch to match the MCP-style JSON-RPC handler.

Testing

• Verified against mcp.stack-auth.com: without this header → 406; with it → request passes Accept validation (no longer 406).

Made with Cursor

Summary by CodeRabbit

• Refactor
  • Updated API request handling to improve content negotiation for doc tools responses, enabling support for multiple response formats.

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[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: 3ca9fe64-39dd-4baf-96f2-a091b112b386

📥 Commits

Reviewing files that changed from the base of the PR and between f78b60b and 13ec595.

📒 Files selected for processing (1)

• apps/backend/src/lib/ai/tools/docs.ts

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📝 Walkthrough

Walkthrough

An HTTP POST request to the docs-tools API endpoint now includes an Accept header alongside Content-Type, indicating the client can handle both JSON and server-sent event responses for improved content negotiation.

Changes

Cohort / File(s)	Summary
Accept Header Addition apps/backend/src/lib/ai/tools/docs.ts	Added Accept header to HTTP POST request advertising support for application/json and text/event-stream response types.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Suggested reviewers

• N2D4

Poem

🐰 A header hops in with grace,
Accept and Content-Type embrace,
JSON flows or streams take flight,
Client speaks its appetite so bright! 📡

🚥 Pre-merge checks | ✅ 2 | ❌ 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 (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title directly and specifically describes the main change: adding an Accept header to the docs-tools MCP endpoint, which is the primary fix in this pull request.
Description check	✅ Passed	The description is well-structured with clear sections (Summary, Change, Testing) that explain the problem, solution, and verification, though it exceeds the minimal template requirements.

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✨ 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/ai-docs-tools-accept-header

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[greptile-apps]

Greptile Summary

Adds the Accept: application/json, text/event-stream header to the postDocsToolAction fetch call, fixing a 406 response from the MCP-style JSON-RPC endpoint at mcp.stack-auth.com that validates clients declare support for both content types. The change is minimal and correctly targets the root cause.

Confidence Score: 5/5

• This PR is safe to merge — it's a one-line targeted fix for a production 406 error with no side effects.
• The change is minimal, well-reasoned, and directly addresses the root cause. The server validates the Accept header but continues to return JSON, so the existing res.json() parsing remains correct. No new logic paths, no regressions.
• No files require special attention.

Important Files Changed

Filename	Overview
apps/backend/src/lib/ai/tools/docs.ts	Adds Accept: "application/json, text/event-stream" header to the internal docs-tools fetch call, fixing a 406 Not Acceptable error from the MCP-style JSON-RPC endpoint that validates this header.

Sequence Diagram

sequenceDiagram
    participant AI as AI Tool (docs.ts)
    participant MCP as mcp.stack-auth.com<br/>/api/internal/docs-tools

    Note over AI,MCP: Before fix
    AI->>MCP: "POST /api/internal/docs-tools<br/>Content-Type: application/json"
    MCP-->>AI: "406 Not Acceptable<br/>(missing Accept header)"

    Note over AI,MCP: After fix
    AI->>MCP: "POST /api/internal/docs-tools<br/>Content-Type: application/json<br/>Accept: application/json, text/event-stream"
    MCP-->>AI: 200 OK (JSON response)
    AI->>AI: res.json() → DocsToolHttpResult

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[Copilot]

Pull request overview

Fixes production 406 responses from the docs-tools MCP endpoint by aligning the backend HTTP client’s Accept header with the MCP server’s content-negotiation requirements.

Changes:

• Add Accept: application/json, text/event-stream to the postDocsToolAction fetch request so requests pass MCP Accept validation.

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