OpenAI App Submission – Tool scan failed: Internal service error

[isaac-b]

We’re in the process of submitting our MCP to the app directory, and get the error “Tool scan failed: Internal service error”.

Troubleshooting:

1. The OAuth flow successfully ran.
2. Using ngrok we confirmed our service was called & returned a valid 200 response for the tool/list.
3. Our full MCP is ~54k tokens, resulting in the 500 error.
4. We truncated the tool/list, and found that the tool scan worked when the MCP definition was below ~32k tokens. This worked with any arrangement of tools; the max-size seemed to be the only limitation.

I’ve submitted a support request to support with specific identifiers. Given the response status is 500, is this a bug?

[isaac-b]