comfyui-mcp

MCP server for ComfyUI. Generate images from natural language prompts in any MCP-compatible client.

Status

v0.2 ships the core tools plus upscale, an image proxy, and public-URL support. Current tool surface: generate_image, generate_variations, generate_with_workflow, refine_image, upscale_image, list_models, list_workflows, upload_image, generate_with_controlnet, generate_with_ip_adapter, plus a workflow template registry. See Roadmap for what's next.

Install

npx (no install required)

npx @miller-joe/comfyui-mcp --comfyui-url http://your-comfyui-host:8188

npm

npm install -g @miller-joe/comfyui-mcp
comfyui-mcp --comfyui-url http://your-comfyui-host:8188

Docker

docker run -p 9100:9100 \
  -e COMFYUI_URL=http://your-comfyui-host:8188 \
  ghcr.io/miller-joe/comfyui-mcp:latest

Connect an MCP client

Claude Code:

claude mcp add --transport http comfyui http://localhost:9100/mcp

Or register the streamable HTTP endpoint with an MCP gateway (e.g. MetaMCP) to aggregate with other servers.

Configuration

All options can be set via CLI flag or environment variable:

Image URLs returned to clients

Generation tools return image URLs like <comfyui-public-url>/view?filename=…. If --comfyui-public-url is not set, URLs use the internal --comfyui-url value.

The server also exposes a proxy endpoint: GET /images/<filename>?subfolder=&type=output streams the image bytes through this server, which is useful when clients can reach the MCP server but not ComfyUI directly.

The default checkpoint must match a file in your ComfyUI models/checkpoints/ directory. Override via COMFYUI_DEFAULT_CKPT or pass checkpoint as a tool argument.

Tools

generate_image

Generate an image from a text prompt using ComfyUI's default txt2img workflow.

Parameters: prompt (required), negative_prompt, width, height, steps, cfg, seed, checkpoint.

generate_variations

Generate multiple variations of the same prompt by varying the seed. Returns all images at once.

Parameters: prompt (required), count (2–16, default 4), plus the same generation params as generate_image, with base_seed instead of seed.

generate_with_workflow

Submit an arbitrary ComfyUI workflow JSON (full node graph) and return the resulting image URLs. Use this for custom workflows — ControlNet, upscaling, or anything exported from ComfyUI's Save (API Format).

Parameter: workflow (object), the complete node graph.

refine_image

Run img2img on a source image. The server fetches a source URL, uploads it to ComfyUI, and runs a denoising pass guided by a new prompt. Lower denoise preserves more of the original; higher gives the prompt more freedom.

Parameters: prompt, source_image_url (required), denoise (0–1, default 0.5), plus standard generation params.

list_models

List available checkpoints, LoRAs, samplers, or schedulers on the ComfyUI instance.

Parameter: kind, one of checkpoints (default), loras,

... View full README on GitHub