Machine Learning

ComfyUI Workflow Builder MCP Server

Connect your account, then chat with AI to run tools.

Build ComfyUI image workflows with an offline node catalog, validate drafts before they hit your GPU, and queue generations on your local machine.

Best forAI ArtistsCreative TechnologistsLocal-First ML Builders

Try this workflow

Starter txt2img graph

Find a basic text-to-image ComfyUI template, validate the API prompt, list my checkpoints, and queue it with a scenic landscape prompt.

—nodes
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Managed
34 tools
Agent guide included

Opens MCPBundles Studio with this server selected. After sign-in, chat and run tools from the same thread.

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What you can do with ComfyUI Workflow Builder

Built for

AI Artists, Creative Technologists, Local-First ML Builders

Example workflows

Starter txt2img graph

Covers discover → validate → list models → run in one ask.

Try this

Find a basic text-to-image ComfyUI template, validate the API prompt, list my checkpoints, and queue it with a scenic landscape prompt.

Inspect KSampler schema

Grounds agents in real object_info schemas instead of guessing.

Try this

Show me the KSampler node inputs from the knowledge index and explain how to wire model, positive, negative, and latent_image.

Fix broken wires

Offline validation catches structural mistakes before GPU time.

Try this

This ComfyUI draft fails validation because a wire references a missing node. Repair the prompt JSON and re-validate before queueing.

Context to know first

Do I need ComfyUI running to search nodes?

No. Searching nodes, templates, and validating drafts works from the materialized index. Queueing workflows and fetching images requires ComfyUI on your machine with Desktop connected.

Where does the node catalog come from?

MCPBundles indexes ComfyUI object_info from your local install (or a pinned snapshot) and refreshes on demand so agents query local evidence instead of live HTTP on every turn.

What workflow JSON shape does ComfyUI expect?

The HTTP API uses an API prompt map: node id strings to [class_type, inputs]. The knowledge tools document wires, output nodes, and common txt2img patterns.

AI Skill
SKILL.md

Domain knowledge for ComfyUI Workflow Builder — workflow patterns, data models, and gotchas for your AI agent.

ComfyUI Workflow Builder

Search node schemas and starter templates offline, validate API prompt JSON, then queue workflows on the user's local ComfyUI GPU through MCPBundles Desktop.

Discovery and draft

  1. Search nodes with comfyui_index_search_nodes; inspect schemas with comfyui_index_get_node.
  2. Pull starter graphs with comfyui_index_search_templates and comfyui_index_get_template.
  3. List checkpoints on the instance with comfyui_list_models before setting ckpt_name.
  4. Assemble API prompt JSON: string node ids → [class_type, inputs] or {class_type, inputs}.
  5. Validate offline with comfyui_index_validate_draft before queueing.

Self-healing build loop

Retry at most three times before stopping and reporting blockers.

  1. Draft offline — finalize nodes and wires; run comfyui_index_validate_draft.
  2. Queue — comfyui_run_workflow with the API prompt; capture prompt_id.
  3. Poll — comfyui_get_history(prompt_id=...) until outputs appear or errors surface.
  4. Fetch — comfyui_get_image with filename/subfolder/type from history outputs.
  5. On failure — read node_errors from queue response or history; fix wires/schemas using the index or comfyui_get_node_info for custom nodes; return to step 1.

Wire and model gotchas

  • Wires are ["source_node_id", output_index] — usually index 0.
  • ckpt_name, LoRA names, and input image filenames must exist on the user's ComfyUI install.
  • Custom nodes may be absent from the offline index — use comfyui_get_node_info live.
  • End with SaveImage or PreviewImage so history exposes downloadable outputs.

Operational notes

  • Catalog search and offline validation need no ComfyUI credential beyond MCPBundles sign-in.
  • Queueing and image fetch require ComfyUI running locally and MCPBundles Desktop connected.
  • Refresh the knowledge index after major ComfyUI upgrades or custom-node installs.

Tools in this Server (34)

Comfyui Clear Queue

Clear pending jobs from the local ComfyUI execution queue. Does not stop the currently running workflow — use comfyui_interrupt for that. Pair with co...

Comfyui Free Memory

Release GPU memory on the local ComfyUI instance. Calls ComfyUI POST /free to unload models and clear execution cache on the next idle tick. Use comfy...

Comfyui Get File

Read a file from the local ComfyUI install on the routed desktop machine. Paths must be relative to input/, output/, or models/. Small files return co...

Comfyui Get History

Read ComfyUI execution history and outputs metadata. Pass prompt_id (returned by comfyui_run_workflow) to fetch one job's outputs, node timing, and st...

Comfyui Get Image

Download a generated image from the local ComfyUI server and return it for visual analysis. Pass filename, subfolder, and type exactly as reported in ...

Comfyui Get Import Fail Info

Read ComfyUI-Manager import failure details for custom node packs. Use when a pack is installed but its node classes do not appear in comfyui_get_node...

Comfyui Get Manager Status

Check whether ComfyUI-Manager is available on the local ComfyUI instance and read its download queue state. Use before comfyui_install_model — Desktop...

Comfyui Get Model Install Status

Poll ComfyUI-Manager for an install queued by comfyui_install_model, comfyui_install_custom_node, or comfyui_install_node_requirements. Pass save_path...

Comfyui Get Node Info

Get the input/output schema for one ComfyUI node class. Use when constructing or debugging workflow JSON for comfyui_run_workflow. Pass the internal c...

Comfyui Get Queue

Get ComfyUI's execution queue: jobs currently running and jobs waiting to run. Use comfyui_get_status for version and hardware info; use this when you...

Comfyui Get Status

Check whether ComfyUI is reachable on the user's machine and summarize runtime state. Returns ComfyUI version, Python/PyTorch versions, GPU/VRAM info ...

Comfyui Get Workflow Template

Return a starter ComfyUI API prompt template for common workloads (SDXL txt2img, SDXL LoRA via FluxTrainer nodes, WAN T2V smoke). Use wan_t2v_native_1...

Comfyui Index Get Guides

List or fetch workflow-building guides for ComfyUI API prompts and the discover-validate-run loop.

Comfyui Index Get Node

Get one node's input/output schema from the knowledge index. For custom nodes not in the index, use comfyui_get_node_info on the live instance.

Comfyui Index Get Template

Fetch one curated template including the API prompt JSON ready for comfyui_run_workflow.

Comfyui Index Search Nodes

Search the materialized ComfyUI node catalog (object_info). Use before building API prompt JSON for comfyui_run_workflow.

Comfyui Index Search Templates

Search curated ComfyUI API prompt templates with starter graphs for common tasks.

Comfyui Index Validate Draft

Validate ComfyUI API prompt JSON offline: node shape, wire references, unknown classes, and missing output nodes. Run before comfyui_run_workflow.

Comfyui Install Custom Node

Install a custom node pack on the local ComfyUI instance via ComfyUI-Manager. Use comfyui_search_custom_node_catalog to discover catalog entries, or p...

Comfyui Install Missing Nodes For Workflow

Detect node classes in a workflow that are not registered on the local ComfyUI instance and queue ComfyUI-Manager installs for matching custom node pa...

Comfyui Install Model

Download a model into the local ComfyUI install via ComfyUI-Manager (same backend as the Manager UI). All fields must match a Manager catalog entry — ...

Comfyui Install Node Requirements

Install or repair Python dependencies for an installed custom node pack via ComfyUI-Manager. Uses the same Manager fix queue as the UI's dependency re...

Comfyui Interrupt

Cancel the workflow ComfyUI is currently executing. Does not remove pending queue items — use only to stop an in-progress generation.

Comfyui List Custom Nodes

List custom node packs installed on the local ComfyUI instance via ComfyUI-Manager. Optionally probe whether specific node classes are registered befo...

Comfyui List Local Files

List files in the local ComfyUI input, output, temp, or models directories. Best for input datasets and models/ checkpoints. After SaveVideo or SaveIm...

Comfyui List Models

List model files available to the local ComfyUI instance for a given folder (checkpoints, loras, vae, etc.). Use the returned filenames when wiring Ch...

Comfyui Put File

Write a file into the local ComfyUI install on the routed desktop machine. Paths must be relative to input/, output/, or models/ — use this to upload ...

Comfyui Reboot Comfyui

Hard-restart the local ComfyUI server through ComfyUI-Manager. Use when comfyui_free_memory cannot reclaim resident VRAM after Flux training or repeat...

Comfyui Reinstall Custom Node

Reinstall a custom node pack via ComfyUI-Manager (uninstall + install). Use when a pack is corrupted or import failures persist after comfyui_install_...

Comfyui Run Workflow

Queue a ComfyUI workflow for execution on the user's local GPU. Pass workflow as the API prompt dict (node id → [class, inputs]). Returns prompt_id an...

Comfyui Search Custom Node Catalog

Search the ComfyUI-Manager custom node catalog on the local ComfyUI instance. Returns node pack metadata for comfyui_install_custom_node. Requires Com...

Comfyui Search Model Catalog

Search the ComfyUI-Manager model install catalog on the local ComfyUI instance. Returns entries with the exact name, type, base, save_path, filename, ...

Comfyui Validate Workflow

Validate a ComfyUI workflow against the live instance: wire references, path shape, and whether each node class is registered. Use before comfyui_run_...

Comfyui Wait For History

Wait until a queued ComfyUI workflow finishes. Default poll_mode=auto tries WebSocket progress (value/max for ETA) then falls back to HTTP poll on kee...

Required Providers (2)

ComfyUI Knowledge

Machine Learning
Materialized ComfyUI node catalog from object_info plus curated API prompt templates and offline workflow validation...
Tools
6 tools
View

ComfyUI

Machine Learning
Run ComfyUI image and video generation workflows on the user's local machine. Queue API-format workflow graphs, inspect...
Tools
28 tools
View

Frequently Asked Questions

What is the ComfyUI Workflow Builder MCP server?

MCP for local ComfyUI: offline node catalog, draft validation, and GPU workflow execution through MCPBundles Desktop. It provides 34 tools that AI agents can use through the Model Context Protocol (MCP).

How do I connect ComfyUI Workflow Builder to my AI agent?

Add the MCPBundles server URL to your MCP client configuration (Claude Desktop, Cursor, VS Code, etc.). The URL format is: https://mcp.mcpbundles.com/bundle/comfyui-workflow-builder. Authentication is handled automatically.

How many tools does ComfyUI Workflow Builder provide?

ComfyUI Workflow Builder provides 34 tools that can be called by AI agents, along with a SKILL.md that gives your AI agent domain knowledge about when and how to use them.

What authentication does ComfyUI Workflow Builder require?

ComfyUI Workflow Builder uses No auth required or API Key. ComfyUI requires credentials. Connect via MCPBundles and authentication is handled automatically.

Do I need ComfyUI running to search nodes?

No. Searching nodes, templates, and validating drafts works from the materialized index. Queueing workflows and fetching images requires ComfyUI on your machine with Desktop connected.

Where does the node catalog come from?

MCPBundles indexes ComfyUI object_info from your local install (or a pinned snapshot) and refreshes on demand so agents query local evidence instead of live HTTP on every turn.

What workflow JSON shape does ComfyUI expect?

The HTTP API uses an API prompt map: node id strings to [class_type, inputs]. The knowledge tools document wires, output nodes, and common txt2img patterns.

Setup Instructions

Connect ComfyUI Workflow Builder to any MCP client in minutes

MCP URL
https://mcp.mcpbundles.com/bundle/comfyui-workflow-builder
Claude.aiCursorVS CodeVS Code InsidersGooseLM StudioCherry StudioChatGPT

One-click install:

Install on Claude.aiInstall for organization (admins)

The link prefills the Add custom connector dialog — you still review the values and click Add, then Connect to complete OAuth.

Or add manually

  1. Open claude.ai → Settings → Connectors.
  2. Click the + button and choose Add custom connector.
  3. Set Name to ComfyUI Workflow Builder and paste the MCP URL into Remote MCP server URL.
  4. Click Add. ComfyUI Workflow Builder will appear under Not connected — select it and click Connect to complete OAuth.
Name: ComfyUI Workflow Builder
Remote MCP server URL: https://mcp.mcpbundles.com/bundle/comfyui-workflow-builder
Authentication: OAuth

Custom connectors at claude.ai require a paid Claude plan (Pro, Max, Team, or Enterprise).

Other ways to use ComfyUI Workflow Builder

Same data, different audiences.

Dataset

ComfyUI Knowledge Index — live data product, refresh cadence + sources documented.

Open dataset

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