Call remote tools via websocket

[alex-schulster]

Hi everyone,

I'm building a setup where a backend SmolAgent (Python, FastAPI) needs to call tools that are defined on a frontend Electron app (renderer process). I want to use MCP over WebSocket for this, with the following constraints:

• The Electron app must not run any extra binary, sidecar, or container
• The Electron client initiates the connection (no open port on the client)
• Communication needs to be real-time and bidirectional
• Tools are defined in the frontend and exposed via MCP over WS
• The backend runs the LLM agent and should be able to call those remote tools

The reason streamable HTTP transport method is not use in this case is because I don't want the client to have to open a port. A websocket initiated by the client seems to be a good solution to this problem but I cannot find a way of implementing this.

Has anyone already done something like this, or even better, has a link to a minimal project demonstrating the implementation? Would be awesome!

Also, if another approach than websockets is more adapted, please share your thoughts!

Cheers!