ComfyUI MCP

Prerequisites

• Node.js >= 22.0.0
• ComfyUI running locally

Install as a plugin

claude plugin install comfyui-mcp

Install a custom node pack

> /comfy:install comfyui-impact-pack

Searches the registry, shows details, clones the repo to custom_nodes/, installs dependencies, and offers to restart ComfyUI.

Setup

git clone https://github.com/artokun/comfyui-mcp.git
cd comfyui-mcp
npm install

Quick Start

1. Install ComfyUI (if you haven't already): ComfyUI Desktop or from source

2. Add the MCP server to your Claude Code config (~/.claude/settings.json):

{
  "mcpServers": {
    "comfyui": {
      "command": "npx",
      "args": ["-y", "comfyui-mcp"],
      "env": {
        "CIVITAI_API_TOKEN": ""
      }
    }
  }
}

3. Start using it. With ComfyUI running, ask Claude to generate an image:

> Generate an image of a sunset over mountains

Claude will find (or download) a checkpoint, build a workflow, execute it, and return the image.

Note: This runs as a standalone MCP server — no need to clone this repo. npx will download and run it automatically.

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Examples

Browse output gallery

> /comfy:gallery last 5
> /comfy:gallery today

Lists recent outputs with embedded metadata — shows checkpoint, prompt, seed, steps, CFG, sampler for each image.

Model Settings

Community-maintained preset library (model-settings.json) with research-backed sampler, scheduler, steps, and CFG values for 10+ model families. User overrides in model-settings.user.jsonc (auto-created from template on install, gitignored).

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Configuration

The server auto-detects your ComfyUI installation and port. Override with environment variables if needed:

Claude Code Plugin

This package also ships as a Claude Code plugin, providing slash commands, skills, agents, and hooks on top of the MCP tools.

Workflow Execution

Workflow Visualization

Workflow Composition

Workflow Validation

Workflow Library

Visualize a workflow

> /comfy:viz ~/workflows/my-workflow.json

Produces a Mermaid diagram with nodes grouped by category:

Debug a failed workflow

> /comfy:debug

Automatically reads the last execution history and logs, identifies the failing node, checks for missing models or node packs, and suggests a fix.

> /comfy:debug abc123-def456

Diagnose a specific execution by prompt ID.

Convert workflow format

> /comfy:convert ~/workflows/my-ui-workflow.json

Converts between ComfyUI's UI format (nodes + links arrays) and API format (node IDs → {class_type, inputs}).

Extract workflow from an image

> Extract the workflow from this image: ~/outputs/ComfyUI_00042_.png

Reads the PNG metadata chunks to recover the exact workflow and prompt used to generate the image.

Compare workflows

> /comfy:compare workflow-a.json vs workflow-b.json

Shows added/removed nodes, changed parameters (old → new values), and optional Mermaid diagrams for visual comparison.

Troubleshooting

"ComfyUI not detected on ports 8188, 8000" Make sure ComfyUI is running. The Desktop app uses port 8000 by default; the CLI uses 8188. Set COMFYUI_PORT if you're using a custom port.

"COMFYUI_PATH is not configured" The auto-detection couldn't find your ComfyUI data directory. Set COMFYUI_PATH to the directory containing your models/ folder (e.g., ~/Documents/ComfyUI).

"Multiple ComfyUI installations detected" This is informational — the server uses the first one found. Set COMFYUI_PATH to pick a specific installation.

Model downloads fail For HuggingFace gated models, set HUGGINGFACE_TOKEN. For CivitAI, set CIVITAI_API_TOKEN.

Workflow execution errors Use /comfy:debug to automatically diagnose failures. Or use get_history / get_logs directly to see detailed error messages including Python tracebacks from ComfyUI.

Out of memory (OOM) Use clear_vram to free GPU memory before running large workflows. The VRAM watchdog hook will warn you automatically if memory is critically low. See the troubleshooting skill for model-specific VRAM estimates.

Missing custom nodes Use /comfy:install <pack> to install missing node packs from the registry. The debug command will detect and suggest missing packs automatically.

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