ComfyUI MCP Server

Connect AI agents to Comfy Cloud for image generation via the Model Context Protocol (MCP)

Early Release: The ComfyUI MCP Server is in early release. Features, tools, and behavior may change as the project evolves.

ComfyUI Cloud MCP Server

The ComfyUI MCP Server connects AI assistants — including Claude Desktop, Claude Code, Cursor, and Amp — to Comfy Cloud via the Model Context Protocol (MCP). It lets AI agents generate images, search models/nodes/templates, and run full ComfyUI workflows on cloud GPUs, with no local GPU required.

Quick Start

1. Get Your API Key

1. Visit https://platform.comfy.org/login and Log In

   Please visit https://platform.comfy.org/login and log in with the corresponding account

   
2. Click `+ New` in API Keys to Create an API Key

   Click + New in API Keys to create an API Key

   
3. Enter API Key Name

   

   1. (Required) Enter the API Key name,
   2. Click Generate to create
4. Save the Obtained API Key

   

   Since the API Key is only visible upon first creation, please save it immediately after creation. It cannot be viewed later, so please keep it safe. Please note that you should not share your API Key with others. Once it leaked, you can delete it and create a new one.

2. Connect Your Client

The ComfyUI MCP Server is hosted at https://cloud.comfy.org/mcp. No local installation or Node.js required — just point your MCP client at the server URL with your API key.

Claude Code

claude mcp add comfyui-cloud \
  --transport http \
  https://cloud.comfy.org/mcp \
  -H "X-API-Key: your-api-key-here"

Claude Desktop

Add the following to your Claude Desktop config file:

OS	Config path
macOS	~/Library/Application Support/Claude/claude_desktop_config.json
Windows	%APPDATA%\Claude\claude_desktop_config.json
Linux	~/.config/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "comfyui-cloud": {
      "url": "https://cloud.comfy.org/mcp",
      "headers": {
        "X-API-Key": "your-api-key-here"
      }
    }
  }
}

Cursor

Add the following to your Cursor MCP config (.cursor/mcp.json in your project or global config):

{
  "mcpServers": {
    "comfyui-cloud": {
      "url": "https://cloud.comfy.org/mcp",
      "headers": {
        "X-API-Key": "your-api-key-here"
      }
    }
  }
}

See Cursor’s MCP documentation for more details.

After adding the server, restart your MCP client to pick up the new configuration.

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Available Tools

Discovery

Tool	Description
search_templates	Search pre-built workflow templates from comfy.org by text, tag, media type, or model
search_models	Search model catalog by text, type, base model, or source
search_nodes	Search available nodes by text, category, or input/output types

Execution

Tool	Description
submit_workflow	Submit a ComfyUI API-format workflow for execution on Comfy Cloud
upload_file	Upload an input image or file for use in workflows (e.g. LoadImage)
get_job_status	Poll execution status of a submitted workflow
get_output	Retrieve output images, videos, or audio from a completed workflow
use_previous_output	Chain workflows by reusing the output of one as input to another
cancel_job	Cancel a pending or running job
get_queue	Check how many jobs are running and pending

Saved Workflows

Tool	Description
list_saved_workflows	Browse your saved workflows from Comfy Cloud
get_saved_workflow	Inspect a saved workflow’s nodes, inputs, and configuration

The server checks for a matching pre-built template before building a workflow from scratch, leading to better results and faster generation.

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How It Works

┌──────────────┐    HTTPS/MCP    ┌─────────────────────────────────────────────┐
│  AI Agent    │◄───────────────►│            Comfy Cloud                      │
│  (Claude,    │   X-API-Key     │  cloud.comfy.org/mcp → Workflow Execution   │
│   Cursor)    │                 │                        on Cloud GPUs        │
└──────────────┘                 └─────────────────────────────────────────────┘

Your AI agent connects directly to the hosted MCP server at cloud.comfy.org/mcp. The server translates MCP tool calls into workflow executions on Comfy Cloud GPUs — no local server or GPU required.

The AI agent already knows how to build ComfyUI API-format workflow JSONs — just describe what you want and it will construct the workflow, submit it, and return the results.

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Example Prompts

After installing, try these prompts in your AI assistant:

Generate an image of a cat astronaut floating in space, cartoon style

Find me workflow templates for text-to-video generation

Search for SDXL checkpoint models and tell me which ones are available

Generate a fantasy landscape with mountains and a glowing river at sunset

What nodes are available for image upscaling?

The agent will search for a matching template, build the ComfyUI workflow, submit it to Comfy Cloud, and return the generated image directly in the conversation.

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Output Handling

• Images are displayed inline (Claude Code) or in the artifact side panel (Claude Desktop)
• Files are saved to ~/Downloads/ComfyUI/ with descriptive filenames (e.g. comfy_cat-astronaut-in-space.png)
• Duplicate filenames are automatically incremented (_1, _2, etc.)
• Pass auto_open: true in the get_output tool call to open files in your default application automatically
• Inline image previews are resized to 1024px (JPEG); full-resolution files are always saved to disk

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Known Limitations

This is an early release. The following limitations are known and being actively worked on.

Workflows

• Cannot run saved workflows by ID. You can browse and inspect saved workflows (list_saved_workflows, get_saved_workflow), but not execute them directly. Saved workflows use the ComfyUI graph format, which requires conversion to API format. The AI agent must reconstruct the workflow from scratch.
• Generated assets have no workflow metadata. Images created via the MCP server don’t include workflow JSON in their metadata, so they won’t show the workflow when opened in ComfyUI.
• Workflow accuracy depends on the AI. The agent constructs ComfyUI workflows from natural language. Complex multi-node workflows or unusual node configurations may require iteration.

File Handling

• Upload size limits may apply depending on your MCP client.
• Image previews are resized. Inline previews are limited to 1024px (JPEG). Full-resolution files are saved to disk.

Authentication

• API key only. Authentication requires a Comfy Cloud API key passed via the X-API-Key header. Browser-based OAuth is not yet available.

Client-Specific

• Claude Desktop — Generated images appear in the artifact side panel via HTML, not as native image artifacts.
• Amp — Status messages during generation may not be surfaced directly. The auto_open feature may not trigger in all contexts.

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Troubleshooting

MCP server not showing up

Restart your MCP client (close and reopen Claude Code, Claude Desktop, or Cursor). MCP servers are loaded at startup. Double-check that the server URL is exactly https://cloud.comfy.org/mcp in your config.

API key errors

Verify your API key is valid at platform.comfy.org/profile/api-keys. Make sure the key is passed in the X-API-Key header (not as a Bearer token). Generate a new key if needed and update your client config.

Connection errors

If the MCP client can’t reach the server, check that:

1. You have an active internet connection
2. Your firewall or proxy isn’t blocking cloud.comfy.org
3. You have an active Comfy Cloud subscription