RunComfy MCP
MCP server for the RunComfy platform โ Serverless API (ComfyUI), Model API, and Trainer API. Manage deployments, run hosted models, train LoRAs, and retrieve results from AI assistants like Claude, Cursor, and Windsurf.
Endpoint: https://mcp.runcomfy.com/mcp
Docs: docs.runcomfy.com/mcp
What it does
31 tools mirroring the RunComfy docs 1:1, across three products plus your account balance.
Serverless API (ComfyUI) โ your own workflows on dedicated endpoints
Docs: docs.runcomfy.com/serverless
| Category | Tools |
|---|
| Deployment management | list_deployments, get_deployment, create_deployment, update_deployment, delete_deployment |
| Inference | submit_request, get_request_status, get_request_result, cancel_request |
| Advanced | call_instance_proxy |
Model API โ hosted catalog models, on demand
Docs: docs.runcomfy.com/model-apis
| Category | Tools |
|---|
| Catalog | list_models, get_model, list_model_categories |
| Inference | run_model, get_model_request_status, get_model_request_result, cancel_model_request |
No deployment to manage and per-request billing. list_models browses the
catalog by keyword or capability (category=image-to-video), get_model
returns one model's input schema โ property types, defaults, enums, and
ranges โ and run_model runs it. So an assistant can go from "make me a
video" to a valid request without leaving the tools or guessing a parameter.
Entries also carry description, base_price_usd per price_unit, and a
model_url to the model's page.
model_id is the identifier shown on the model's page at
runcomfy.com/models, slashes included โ e.g.
blackforestlabs/flux-1-kontext/pro/edit. File inputs must be public HTTPS URLs.
Docs: docs.runcomfy.com/trainer-apis
| Category | Tools |
|---|
| Datasets | create_dataset, list_datasets, get_dataset_status, delete_dataset |
| Dataset uploads | upload_dataset_file_from_url, upload_dataset_text_file, get_dataset_upload_urls |
| Training jobs | submit_training_job, get_training_job_status, get_training_job_result, cancel_training_job, resume_training_job, edit_training_job |
Typical flow: create a dataset โ upload media and matching .txt captions โ
poll until READY โ submit a job with an AI Toolkit YAML config โ poll status
โ pull checkpoints from the result.
Because the server runs remotely it cannot read local files. Upload media it
can reach over HTTP with upload_dataset_file_from_url, write captions inline
with upload_dataset_text_file, and for local or >150 MB files use
get_dataset_upload_urls and PUT the bytes to the signed URL yourself.
Account
| Category | Tools |
|---|
| Balance | get_balance |
One wallet funds all three products. get_balance reports what is left, in
balance_usd for reading and balance_microdollars (millionths of a dollar)
for exact threshold checks. It is served from api.runcomfy.net rather than
mirrored per product, because there is only one figure to report.
Crossing between them
A trained LoRA runs without any deployment: pass its base model's model_id
to run_model and the LoRA as an input, e.g.
{"lora": {"path": "my_first_lora_3000.safetensors"}} โ either a name from
your LoRA Assets or a public
URL such as a checkpoint from get_training_job_result. For a dedicated
endpoint with chosen hardware, deploy it and use the Serverless tools instead.
Quick setup
Every client authenticates with a RunComfy API token from your
Profile page. Two ways to supply it:
- API token header โ works in any Streamable HTTP client. Simplest, and the
only option for clients without a browser OAuth flow.
- Browser OAuth โ no token in a config file. Supported by Claude.ai, Cursor,
and local clients that register a loopback callback, such as Claude Code.
Claude Code
Token header (one command, nothing else to do):
claude mcp add --transport http runcomfy https://mcp.runcomfy.com/mcp --header "Authorization: Bearer YOUR_RUNCOMFY_TOKEN"
Or browser OAuth โ omit the header, then run /mcp inside Claude Code and pick
Authenticate:
claude mcp add --transport http runcomfy https://mcp.runcomfy.com/mcp
--transport http is the Streamable HTTP transport. streamable-http is not a
value Claude Code accepts, and single-dash -transport / -header are not
either โ both forms fail before the server is ever contacted.
Check it with claude mcp list, which should show runcomfy: connected.
Claude.ai
Add https://mcp.runcomfy.com/mcp in Settings โ Connectors โ Add custom
connector, then select Connect. Claude discovers RunComfy's OAuth 2.1
endpoints, opens a RunComfy consent page, and asks for one of the API tokens
shown in your RunComfy Profile. The token
is validated by RunComfy and encrypted inside the MCP authorization grant; it
is never returned to Claude.
Cursor
.cursor/mcp.json:
{
"mcpServers": {
"runcomfy": {
"url": "https://mcp.runcomfy.com/mcp",
"headers": { "Authorization": "Bearer YOUR_RUNCOMFY_TOKEN" }
}
}
}
VS Code (Copilot)
.vscode/mcp.json:
{
"servers": {
"runcomfy": {
"type": "http",
"url": "https://mcp.runcomfy.com/mcp",
"headers": { "Authorization": "Bearer YOUR_RUNCOMFY_TOKEN" }
}
}
}
Windsurf
Settings โ MCP:
{
"mcpServers": {
"runcomfy": {
"serverUrl": "https://mcp.runcomfy.com/mcp",
"headers": { "Authorization": "Bearer YOUR_RUNCOMFY_TOKEN" }
}
}
}
Any other client
- URL:
https://mcp.runcomfy.com/mcp
- Transport: Streamable HTTP
- Auth:
Authorization: Bearer <token> on every request, or OAuth 2.1 with
a loopback redirect URI or an exact supported client callback
Troubleshooting
| Symptom | Cause |
|---|
401 with RunComfy rejected this API token | The token is wrong, expired, or truncated on copy. Generate a new one in Profile โ the response body names the fix. |
401 with no error_description | No Authorization header reached the server. Check the header is quoted as one argument: --header "Authorization: Bearer ...". |
invalid_client_metadata during OAuth | The client registered a callback outside the loopback and exact client allowlist. Use a supported callback or the token header. |
invalid_target during OAuth | The configured URL must be exactly https://mcp.runcomfy.com/mcp โ no trailing slash. RFC 8707 binds the token to that exact resource. |
503 with Retry-After | RunComfy's API could not be reached to verify the token. Retry. |
429 | More than 600 token-authenticated requests a minute from one IP. |
Revoke access by regenerating the token in your RunComfy Profile. That
invalidates the token header and any OAuth grant built on it, because every MCP
request revalidates the token upstream.
Architecture
MCP Client โโRunComfy API tokenโโโ
โ Cloudflare Worker (/mcp)
MCP Client โโMCP OAuth tokenโโโโโโค validates the credential, resolves
โ it to one user's RunComfy token
โผ
Cloudflare Container
(Python FastMCP app)
โ request-scoped RunComfy credential
โโโโโโโโโโโโโโโโโผโโโโโโโโโโโโโโโโ
โผ โผ โผ
api.runcomfy.net model-api. trainer-api.
(Serverless) runcomfy.net runcomfy.net
(Model) (Trainer)
One RunComfy token authenticates all three products, so the same credential
resolution covers every tool.
Both credential kinds converge on the same request-scoped identity header
before the container is reached. They are told apart by shape: OAuth access
tokens are always userId:grantId:secret, and a RunComfy API token never
contains a colon.
- Cloudflare Worker (
src/index.ts) โ OAuth 2.1 authorization server and protected-resource boundary. Missing, invalid, expired, or wrong-audience credentials are rejected before MCP initialization or tool discovery.
- Direct API token (
src/index.ts) โ a RunComfy Profile token presented as Authorization: Bearer is revalidated against api.runcomfy.net on every request, rate-limited per source IP, and never forwarded as-is.
- OAuth consent (
src/oauth-bridge.ts) โ validates an existing RunComfy Profile token, stores it only in encrypted OAuth grant data, and issues a separate audience-bound MCP access token. Dynamic client registration accepts loopback callbacks (Claude Code and other local clients), an exact allowlist of hosted client callbacks, and Cursor's exact legacy app callback. Cursor registers cursor://anysphere.cursor-mcp/oauth/callback, https://www.cursor.com/agents/mcp/oauth/callback, and http://localhost:8787/callback together; all three must be accepted even when the active redirect uses localhost. Arbitrary custom protocols and callback variants remain rejected, and S256 PKCE is required.
- Python container (
server.py) โ FastMCP app with 31 tools across the Serverless, Model, and Trainer APIs. It has no shared/operator credential and fails closed unless the authenticated edge supplies the current user's request-scoped RunComfy token.
- Cloudflare Container auto-starts on first request, sleeps after 10 minutes idle.
Project layout
.github/workflows/deploy.yml CI: typecheck, test, deploy to Cloudflare
src/index.ts Cloudflare Worker entrypoint
src/oauth-bridge.ts OAuth consent and RunComfy token validation
server.py MCP tool definitions (31 tools)
runcomfy_client.py RunComfy API clients (serverless, model, trainer)
container_app.py ASGI middleware (request IDs, token forwarding)
container_entrypoint.py Uvicorn startup
container_runtime.py Env validation, structured logging
wrangler.jsonc Cloudflare Worker + Container config
Dockerfile Container image
.env.example Local dev config
Local development
python3.11 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
cp .env.example .env
python -m container_entrypoint
Local endpoints:
http://127.0.0.1:8000/healthz
http://127.0.0.1:8000/mcp
The local Python endpoint intentionally has no shared fallback credential.
Protected tool calls must go through the authenticated Worker boundary.
Deploy
Pushing to main deploys automatically via .github/workflows/deploy.yml:
typecheck, Worker tests, and container tests must pass, then
wrangler deploy --containers-rollout immediate ships the Worker and the
Python container together. Pull requests run the same checks without
deploying. The workflow can also be run by hand from the Actions tab.
One repository secret is required:
| Secret | Purpose |
|---|
CLOUDFLARE_API_TOKEN | A token with Edit Cloudflare Workers permission on the account in wrangler.jsonc |
CLOUDFLARE_ACCOUNT_ID | Optional. account_id is already committed in wrangler.jsonc; set this only to deploy under a different account. |
To deploy by hand (requires Cloudflare Workers Paid plan with Containers enabled):
npm install
npm run check
npm test
npx wrangler deploy --containers-rollout immediate
The MCP endpoint goes live at https://mcp.runcomfy.com/mcp (custom domain configured in wrangler.jsonc).
Environment variables and bindings
There is deliberately no shared RunComfy API-key secret. OAuth state is kept
in the OAUTH_KV binding and every upstream request is tied to the user who
authorized the OAuth grant.
Worker vars (in wrangler.jsonc)
| Name | Default | Description |
|---|
CONTAINER_INSTANCE_NAME | runcomfy-unified | Durable Object instance name |
CONTAINER_STARTUP_TIMEOUT_MS | 15000 | Max wait for container start |
CONTAINER_PORT_READY_TIMEOUT_MS | 30000 | Max wait for port ready |
MCP_MAX_BODY_BYTES | 1048576 | Max request body size |
OPENAI_APPS_CHALLENGE | Current submission token | Public OpenAI domain-verification token, served verbatim at GET /.well-known/openai-apps-challenge; unset or empty returns 404. Verify ownership of any existing token before replacing it. |
MCP_DIRECT_TOKEN_RATE_LIMITER | 600 / 60s | Per-IP cap on API-token-authenticated /mcp requests |
RUNCOMFY_SERVERLESS_BASE_URL | https://api.runcomfy.net | Serverless API base URL |
RUNCOMFY_MODEL_API_BASE_URL | https://model-api.runcomfy.net | Model API base URL |
RUNCOMFY_TRAINER_API_BASE_URL | https://trainer-api.runcomfy.net | Trainer API base URL |
Local Python dev (.env file)
| Name | Required | Description |
|---|
RUNCOMFY_SERVERLESS_BASE_URL | No | Override Serverless base URL (default: https://api.runcomfy.net) |
RUNCOMFY_MODEL_API_BASE_URL | No | Override Model API base URL (default: https://model-api.runcomfy.net) |
RUNCOMFY_TRAINER_API_BASE_URL | No | Override Trainer API base URL (default: https://trainer-api.runcomfy.net) |
RUNCOMFY_MCP_MOUNT_PREFIX | No | Path prefix for MCP mount (default: empty) |