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.