ComfyUI MCP Server

1. Overview

A server implementation for integrating ComfyUI with MCP.
⚠️ IMPORTANT: This server requires a running ComfyUI server.
- You must either host your own ComfyUI server,
- or have access to an existing ComfyUI server address.

2. Debugging

2.1 ComfyUI Debugging

python src/test_comfyui.py

2.2 MCP Debugging

mcp dev src/server.py

3. Installation and Configuration

3.1 ComfyUI Configuration

Edit src/.env to set ComfyUI host and port:

COMFYUI_HOST=localhost
COMFYUI_PORT=8188

3.2 Adding Custom Workflows

To add new tools, place your workflow JSON files in the workflows directory and declare them as new tools in the system.

4. Built-in Tools

text_to_image
- Returns only the URL of the generated image.
- To get the actual image:
  - Use the download_image tool, or
  - Access the URL directly in your browser.
download_image
- Downloads images generated by other tools (like text_to_image) using the image URL.
run_workflow_with_file
- Run a workflow by providing the path to a workflow JSON file.
```
# You should ask to agent like this.
Run comfyui workflow with text_to_image.json
```
- example image of CursorAI

run_workflow_with_json

Run a workflow by providing the workflow JSON data directly.

# You should ask to agent like this.
Run comfyui workflow with this 
{
  "3": {
      "inputs": {
          "seed": 156680208700286,
          "steps": 20,
    ... (workflow JSON example)
}

5. How to Run

5.1 Using UV (Recommended)

Example mcp.json:

{
  "mcpServers": {
    "comfyui": {
      "command": "uv",
      "args": [
        "--directory",
        "PATH/MCP/comfyui",
        "run",
        "--with",
        "mcp",
        "--with",
        "websocket-client",
        "--with",
        "python-dotenv",
        "mcp",
        "run",
        "src/server.py:mcp"
      ]
    }
  }
}

5.2 Using Docker

Downloading images to a local folder with download_image may be difficult since the Docker container does not share the host filesystem.
When using Docker, consider:
1. Set RETURN_URL=false in .env to receive image data as bytes.
2. Set COMFYUI_HOST in .env to the appropriate address (e.g., host.docker.internal or your server's IP).
3. Note: Large image payloads may exceed response limits when using binary data.

5.2.1 Build Docker Image

# First build image
docker image build -t mcp/comfyui .

{
  "mcpServers": {
    "comfyui": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-p",
        "3001:3000",
        "mcp/comfyui"
      ]
    }
  }
}

5.2.2 Using Existing Images

Also you can use prebuilt image.

{
  "mcpServers": {
    "comfyui": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-p",
        "3001:3000",
        "overseer66/mcp-comfyui"
      ]
    }
  }
}

5.2.3 Using SSE Transport

Run the SSE server with Docker:

docker run -i --rm -p 8001:8000 overseer66/mcp-comfyui-sse

Configure mcp.json (change localhost to your IP or domain if needed):

{
  "mcpServers": {
    "comfyui": {
      "url": "http://localhost:8001/sse" 
    }
  }
}

NOTE: When adding new workflows as tools, you need to rebuild and redeploy the Docker images to make them available.

ComfyUI Integration