MCP connector creation times out despite successful initialize & tools/list (openai-mcp/1.0.0)

Hi all — we’re running into a connector creation timeout that appears to be client-side / platform-side rather than server-side, and wanted to check if others are seeing the same.

Summary

When adding a custom MCP server as a connector in ChatGPT, the UI errors with “Error creating connector — Request timeout”, even though the MCP server successfully handles all expected calls.

What we’re seeing in server logs

  • Requests from User-Agent: openai-mcp/1.0.0

  • initialize200 OK in ~0–32 ms

  • tools/list200 OK, full tool list returned

  • No redirects (301/302)

  • HTTPS valid

  • No errors, crashes, or restarts

  • CSP / CORS explicitly allow chat.openai.com and chatgpt.com

What we’ve verified

  • MCP endpoint is mounted exactly at /mcp

  • No trailing slash redirects

  • Curl tests succeed:

    • POST /tools/list

    • Requests with Accept: text/event-stream

  • Railway service is warm (no cold-start delay)

  • Tool schemas and outputs are valid JSON

  • Same behavior across retries

Despite this, the ChatGPT UI still times out during connector creation.

Hypothesis

It seems the MCP handshake succeeds, but the UI may be timing out on a post-validation step (internal safety scan, tool eligibility check, caching, or connector metadata processing), rather than on the MCP server itself.

We’ve seen similar reports where:

  • initialize/tools/list succeed

  • UI still times out or fails creation

  • behavior appears intermittent or rollout-related

Questions

  1. Is anyone else seeing connector creation timeouts even when MCP calls are fast and correct?

  2. Are there known limits around:

    • tool count

    • schema size

    • connector metadata processing

  3. Is this a known incident or regression with MCP connectors / Apps SDK right now?

Happy to provide sanitized logs or try any suggested mitigations (minimal tool mode, schema reduction, etc.).
Thanks in advance — appreciate any confirmation or guidance.

Have just seen this exact same thing happen when adding ours. Did you ever find a solution?

The MCP server is working perfectly when accessed by the same URL and this final step is driving me crazy!

Cheers

Hey Everyone, Can someone please confirm if this is still an issue? We are more than happy to help.