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Teknium
dd2dc2bddf
fix(mcp): forward OAuth auth and bump sse_read_timeout on SSE transport (#21323)
* fix(mcp): re-raise CancelledError explicitly in MCPServerTask.run

On Python 3.11+, `asyncio.CancelledError` inherits from `BaseException`
(not `Exception`), so the broad `except Exception as exc:` in
`MCPServerTask.run`'s transport loop did NOT catch it. Task cancellation
from gateway restart / explicit `task.cancel()` silently escaped past
the reconnect logic — the MCP server task died without going through
the shutdown/reconnect code paths that check `_shutdown_event`.

Add an explicit `except asyncio.CancelledError: raise` before the broad
catch so cancellation propagation is self-documenting rather than an
accident of exception hierarchy, and future sibling-site work (e.g.
distinguishing shutdown-cancel from transport-cancel) has an obvious
hook. Behavior on pre-3.8 Pythons where CancelledError WAS an Exception
subclass is also corrected: the old path would have caught it and
treated it as a connection failure worth retrying.

Closes #9930.

* fix(mcp): forward OAuth auth and bump sse_read_timeout on SSE transport

Two surgical correctness bugs in the SSE branch of MCPServerTask._run_http,
distilled from @amiller's PR #5981 that couldn't be cherry-picked wholesale
(branch too stale).

1. sse_read_timeout was set to the tool timeout (default 60s). That's the
   wrong dimension — it governs how long sse_client will wait between
   events on the SSE stream, not per-call latency. SSE servers routinely
   hold the stream idle for minutes between events; a 60s read timeout
   drops the connection after the first slow stretch (Router Teamwork,
   Supermemory on Cloudflare Workers idle-disconnect at ~60s). Bump to
   300s to match the Streamable HTTP path's httpx read timeout.

2. OAuth auth was built via get_manager().get_or_build_provider() but
   never forwarded to sse_client. SSE MCP servers behind OAuth 2.1 PKCE
   would silently fail with 401s on every request.

Keepalive (the other half of #5981) intentionally left for a follow-up —
it's a real improvement but a bigger change, and these two are obvious
corrections to ship now. Credits to @amiller.

Co-authored-by: Andrew Miller <socrates1024@gmail.com>

---------

Co-authored-by: Andrew Miller <socrates1024@gmail.com>
2026-05-07 07:08:04 -07:00