Fix: GET on the MCP endpoint answers fast (not a held-open hang)
Web-audit fix skill for the
mcp-get-fast-failcheck (MCP, SHOULD).
Goal
Answer GET with 405 or an SSE stream, never a document and never a held-open hang.
Fix
Answer a GET on the MCP endpoint promptly, and answer it as streamable HTTP defines. The probe sends Accept: text/event-stream. A 200 whose Content-Type is text/html, text/markdown, or any other non-SSE type fails: a catalog client treats that document as a transport error. Return one of two answers. Fast-fail at the router with 405 Method Not Allowed, Allow: POST, and Cache-Control: no-store. Or return 200 with Content-Type: text/event-stream and an SSE body. Put the human-readable description on a different path. A held-open connection and a 5xx also fail. A 408 or 429 asks to be retried and is not scored.
Resources
Copy-paste prompt
Paste this into your coding agent. Your audit adds what it observed for this check:
Verify
Re-run the audit at https://anc.dev/audit or call the audit_website MCP tool; the mcp-get-fast-fail check should report pass.