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:

1. Load your workflow with comfy_load_workflow
2. Upload the image with comfy_upload_image
3. 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.