Can't get the mcp-run-python MCP to work

[simonw]

I tried these settings:

And I get this error:

Running this command in a terminal seems to work without error:

deno run -N -R=node_modules -W=node_modules --node-modules-dir=auto jsr:@pydantic/mcp-run-python stdio

I'm using this: https://ai.pydantic.dev/mcp/run-python/

[paulhugel]

Step 3 – Register the MCP server in Jan AI

1. Open Jan AI → Settings → Integrations (or the Add MPC Server panel).
2. Click “Add New MPC Server.”
3. Fill in the fields as shown below:

Field	Value / Example
Name	JanAI-Demo (must match the name given to FastMCP)
Transport	stdio (use HTTP only after switching to run_http())
Command	uv run server.py
Working Directory	Path to the folder that contains server.py (e.g. /home/user/jan-mcp-server)
Environment Variables	(optional) PYTHONPATH=. if you have extra modules
Timeout (seconds)	30 (default works for most cases)

4. Press Save. Jan AI will launch the process, perform an MCP handshake, and list the discovered tools (e.g., echo, add).

Tip: After confirming the tools work locally, you can switch the transport to HTTP, update the command to run_http(host="0.0.0.0", port=8000), redeploy the server, and then set Transport → HTTP with the server’s base URL (e.g., https://jan-mcp.myorg.com).