Reworks the content-type preflight so a misconfigured HTTP MCP url (a web-app
root serving HTML) fails in <1s instead of hanging the full 60s connect_timeout
— and does so non-retryably, which neither original PR achieved.
- Allow-list detection (application/json, text/event-stream) instead of a
text/html-only denylist — catches text/plain, application/xml, etc.
- New NonMcpEndpointError(ConnectionError); run() catches it in the same
top-level fast-fail block as InvalidMcpUrlError, so it returns before the
reconnect-backoff loop (truly non-retryable) and the probe runs once, not
on every reconnect.
- Probe runs on its own httpx client OUTSIDE the SDK anyio task group, so the
error propagates as itself rather than wrapped in an ExceptionGroup (the
trap that made the in-SDK event-hook approach a no-op).
- Forwards ssl_verify + client_cert + headers; HEAD->GET fallback on 405/501;
best-effort pass-through on missing content type, non-2xx, and network
errors; skips SSE transport. CancelledError is never swallowed.
- Replaces the malformed test file (which never imported the real method and
failed CI) with 21 tests driving the actual _preflight_content_type against
a real local HTTP server, plus full run() integration verifying <1s
non-retryable failure.
Co-authored-by: liuhao1024 <sunsky.lau@gmail.com>
Co-authored-by: uzunkuyruk <egitimviscara@gmail.com>
64f7f36713