MCP (and plugins) not working with Custom Engines?

[kilkelly]

I can't seem to get MCP and plugins to work with a Custom Engine. I'm able to chat with the Custom Engine but none of the MCP / plugins seem to activate. From my knowledge of MCP, the LLM should receive some text describing the tools and parameters available to it, but this seems to be absent in the system prompt.

The MCP I'm trying to use is https://github.com/kazuph/mcp-youtube. The interface indicates that it gets installed and is running correctly (✅)

Custom Engine

Installed MCP ✅

Debug console (no tool text visible in system prompt?)

Love this app BTW.

[nbonamy]

The tool description is visible in the bottom of your second screenshot. They are provided as part of the whole payload not in the system prompt

[kilkelly]

Thanks @nbonamy. I'm guessing then it's an issue with the third-party's implementation of the OpenAI spec i.e. not handling the tools field correctly?

[nbonamy]

Not sure why you think there is an issue?

[kilkelly]

I suspect the LLM provider (which I configured in the Custom Engine) is not consuming the tools field according to the spec. I have contacted them to clarify.

[nbonamy]

I'll close this then. Do not hesitate to reopen if needed.

[kilkelly]

Much appreciated @nbonamy 👍