Process Control - ComfyUI MCP

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restart_comfyui

Control the lifecycle of the ComfyUI server process. Driven by the action parameter:

action:“restart” — Restart ComfyUI: stops the running process (capturing its config), waits for the port to free, relaunches with the same arguments, and polls the API for bounded readiness. Also works against a REMOTE/tunnelled ComfyUI (via —comfyui-url) by rebooting through ComfyUI-Manager over HTTP and polling for it to come back (requires ComfyUI-Manager present and its security level permitting the reboot). This is the normal way to reload newly installed custom nodes, and the escalation when queue (action:“cancel”) reports a job WEDGED.
action:“start” — Start ComfyUI using process info saved from a previous action:“stop” call. Supports both Desktop app and manual Python installs. Polls the API for bounded readiness before reporting ready. Local installs only.
action:“stop” — Stop the running ComfyUI process. Captures process info so it can be restarted with action:“start”. Kills the process tree and resets the WebSocket client. Local installs only. Anything queued or rendering is lost.

In plain terms: Starting, stopping and restarting ComfyUI, chosen with action. Restarting is the standard next step after installing a node pack — new nodes are not loaded until ComfyUI starts again.

Parameters

enum

required

Which process operation to perform. None of them takes any other parameter. “restart” stops and relaunches in one call (and is the only action that also works against a remote/tunnelled ComfyUI); “start” relaunches from the info a previous “stop” saved; “stop” kills the running process tree. Options: action:"restart", action:"start", action:"stop".

Examples

You say: Restart it so the new nodes load.

{
  "tool": "restart_comfyui",
  "arguments": {
    "action": "restart"
  }
}

You get back: The server stops and comes back up, and you are told when it is answering again.

Anything queued or rendering is lost. Check the queue is empty first if a long job is in flight.

You say: Shut ComfyUI down, I need the VRAM.

{
  "tool": "restart_comfyui",
  "arguments": {
    "action": "stop"
  }
}

You get back: Confirmation that the process stopped.

Any running or queued render is lost.

You say: Start ComfyUI again.

{
  "tool": "restart_comfyui",
  "arguments": {
    "action": "start"
  }
}

You get back: It launches the server and waits until it is answering, then tells you the URL. Only works for a ComfyUI on this machine.

​restart_comfyui

​Parameters

​Examples

restart_comfyui

Parameters

Examples