FastMCP with OAuth and ChatGPT

[sm-mbrt]

Hi!

Wasn't sure where to ask this, so trying here - sorry if this isn't the ideal spot.

I've built an MCP server targeting protocol rev 2025-06-18 (auth is a separate service). I'm using FastMCP v2.11.3 as the resource server with JWTVerifier + RemoteAuthProvider.
Everything works fine in MCP Inspector and Claude (web).
Where I’m hitting friction is with ChatGPT (Team plan):

• when adding the connector it tries GET /.well-known/oauth-authorization-server - server returns 404

• and it doesn't probe / with HEAD/GET to get a 401 and discover via the header that points to /.well-known/oauth-protected-resource etc.

As a result client shows "Error fetching OAuth configuration."

Has anyone here successfully connected a FastMCP server to ChatGPT Team recently?
If yes, did you expose /.well-known/oauth-authorization-server as a compatibility shim?