ComfyUI MCP Server

A Model Context Protocol (MCP) server that enables Claude Desktop to interact with your local ComfyUI installation for AI-powered image generation.

Features

15 MCP Tools for complete ComfyUI control
Template-based generation (Flux, SD1.5, SDXL, img2img)
Custom workflow execution with smart parameter overrides
Real-time progress monitoring via WebSocket
Model management (list checkpoints, LoRAs, VAEs, etc.)
Workflow library for saving and reusing workflows
Queue management (status, cancel, clear)
Image upload/retrieval with full Windows path support

Prerequisites

Node.js v20 or higher
ComfyUI installed and running at http://127.0.0.1:8188
Claude Desktop (for MCP integration)
Windows 11 (as per specification)

Installation

1. Install Dependencies

[!NOTE] The file paths in the examples below must be replaced with the correct paths for your system.

cd [Path to your ComfyUI MCP Server]
npm install

2. Configure Paths

Edit config.json to match your ComfyUI installation:

{
  "comfyui": {
    "installation_path": "[Path to your ComfyUI portable installation]"
  }
}

3. Build the Server

npm run build

4. Configure Claude Desktop

Edit %APPDATA%\Claude\claude_desktop_config.json:

{
  "mcpServers": {
    "comfyui": {
      "command": "node",
      "args": [
        "[Path to your ComfyUI MCP Server]\\dist\\index.js"
      ],
      "env": {
        "COMFYUI_CONFIG": "[Path to your ComfyUI MCP Server]\\config.json"
      }
    }
  }
}

5. Restart Claude Desktop

The ComfyUI tools will now be available in Claude Desktop.

Available Tools

Generation

comfy_submit_workflow - Submit custom workflow JSON with overrides
comfy_generate_simple - Quick generation using templates

Status & Monitoring

comfy_get_status - Check generation status and outputs
comfy_wait_for_completion - Wait for generation to complete

Model Management

comfy_list_models - List available models, LoRAs, VAEs

Workflow Library

comfy_save_workflow - Save workflow to library
comfy_load_workflow - Load saved workflow
comfy_list_workflows - List all saved workflows
comfy_delete_workflow - Delete workflow from library

Queue Management

comfy_get_queue - Get current queue status
comfy_cancel_generation - Cancel generation
comfy_clear_queue - Clear pending queue items

Utilities

comfy_upload_image - Upload image to ComfyUI input folder
comfy_get_output_images - List recent output images

Usage Examples

Simple Text-to-Image Generation

Ask Claude:

Generate an image of a sunset over mountains using Flux

Claude will use comfy_generate_simple with the flux_txt2img template.

Custom Workflow Execution

Use my chrono_edit workflow to animate this product image

Claude will:

Load your workflow with comfy_load_workflow
Upload the image with comfy_upload_image
Submit with comfy_submit_workflow and parameter overrides

Check Available Models

What Flux models do I have available?

Claude will use comfy_list_models with filter="flux".

Configuration

Template Defaults

Edit config.json to customize template defaults:

{
  "templates": {
    "flux_txt2img": {
      "default_model": "flux_dev.safetensors",
      "default_steps": 20,
      "default_cfg": 3.5
    }
  }
}

Workflow Library Path

Workflows are saved to:

[Path to your ComfyUI portable installation]\ComfyUI\user\default\workflows\mcp_library

Troubleshooting

"Cannot connect to ComfyUI"

Ensure ComfyUI is running: run_nvidia_gpu.bat
Check ComfyUI is accessible at http://127.0.0.1:8188
Verify port 8188 is not blocked by firewall

"Model not found"

Run comfy_list_models to see available models
Check model file exists in the correct folder
Verify model name spelling matches exactly

"Workflow validation failed"

Test workflow in ComfyUI UI first
Check all node connections are valid
Ensure all required models are available

Permission Errors

Check folder permissions on ComfyUI directories
Run Claude Desktop as administrator if needed
Verify paths in config.json are accessible

Development

Build in Watch Mode

npm run dev

Clean Build

npm run clean
npm run build

Architecture

Claude Desktop (stdio) → MCP Server → ComfyUI API (HTTP/WebSocket)
                              ↓
                         File System
                         - Models
                         - Input/Output
                         - Workflow Library

The MCP server runs as a separate Node.js process and communicates with ComfyUI via its HTTP API and WebSocket connections. It does not modify any ComfyUI files.

License

MIT

Support

For issues and questions, refer to the specification document or ComfyUI API documentation.