Error with request ID not integer

[stefanolissa]

Hi, trying to expose an MCP server and connect with Mistral, I get this error:

Unexpected error in handle_mcp_request | Context: {"transport":"WP\\MCP\\Transport\\Infrastructure\\HttpRequestHandler","server_id":"mcp1","error":"WP\\MCP\\Infrastructure\\ErrorHandling\\McpErrorFactory::internal_error(): Argument #1 ($id) must be of type int, string given, called in .../plugins\/satollo-mcpservers\/vendor\/wordpress\/mcp-adapter\/includes\/Transport\/Infrastructure\/RequestRouter.php on line 130"} | User ID: 2

And actually Mistral is sending as request ID a UUID (string). I don't know if this is a bug in the adapter or a problem in Mistral. The MCP standard seems to allows string as a request ID.

Since the error happens during the "initialize" command, I think the problem is in the signature of the method InitializeHandler:: handle() requiring an int for the $request_id (even if not used inside the method.

Thanks, Stefano.

[stefanolissa]

I can confirm that patching the InitializeHandler the connection with Mistral works.

[galatanovidiu]

Hi Stefano, thanks for the detailed report.

You're right, the MCP spec allows both string and integer request IDs. The int type hint on InitializeHandler::handle() was the problem.

This was fixed on trunk as part of a larger refactor. The handler no longer takes the request ID directly, and the full chain (RequestRouter, handlers, McpErrorFactory, schema DTOs) now accepts string|int|null IDs throughout.

If you're installing via Composer, you're likely on v0.4.1 (the latest tagged release) which still has the bug. I'm hoping to get v0.5.0 out by end of this week, which will include the fix. In the meantime, switching to dev-trunk should unblock you.

The call for testing on v0.5.0 hasn't gone out yet, but I'd really appreciate it if you could give it a spin and let me know how it goes with Mistral.

[stefanolissa]

Just tested, it works, thank you!