ComfyUI Builder MCP server

Read from the package source without running it. The installed server may list more.

• add_node

  Add a node to a dynamic workflow. Returns the new node id (e.g. "1", "2").

• apply_template

  Apply parameter values to a workflow template. Returns workflow JSON ready to execute or save. Use create_template to build a template, then apply_template with values.

• build_workflow

  Build a ComfyUI workflow from a template and parameters. Returns workflow JSON ready to execute or save. For txt2img_flux, call get_system_resources first and use only when flux_ready is true (FLUX needs ~12GB+ VRAM).

• check_compatibility

  Check if output of one node can connect to input of another (using node-compatibility.json).

• check_model_exists

  Check if a model exists on the ComfyUI server (in object_info model lists). Requires COMFYUI_HOST.

• check_workflow_models

  Check which models required by a workflow exist on the ComfyUI server. Returns ready (boolean), missing, and found lists. Requires COMFYUI_HOST.

• clear_queue

  Clear ComfyUI queue: remove all pending and stop/clear running. Requires COMFYUI_HOST.

• connect_nodes

  Connect an output of one node to an input of another in a dynamic workflow.

• create_templatewrite action

  Create a parameterized workflow template from a workflow and parameter definitions. Returns template JSON for use with apply_template or validate_template_params. Parameters bind to node inputs via nodeBindings (nodeId, inputName).

• create_workflowwrite action

  Create a new empty workflow context. Returns workflow_id to use with add_node, connect_nodes, get_workflow_json, validate_workflow, finalize_workflow, execute_workflow.

• delete_queue_itemswrite action

  Remove specific items from ComfyUI queue by prompt_id. Use list_queue to get prompt_ids. Requires COMFYUI_HOST.

• discover_nodes_live

  Get all node definitions from the running ComfyUI instance (GET /object_info). Returns class names and categories. Requires ComfyUI to be running at COMFYUI_HOST.

• download_all_outputs

  Download all output files for a prompt into a directory. Returns list of saved paths. Requires COMFYUI_HOST.

• download_by_filename

  Download an output file by filename (no prompt_id needed). Uses GET /view. Use when you have filename from get_history or get_last_output. If return_base64 is true, file is not written to disk; returns base64 data. When size > 800 KB, automatically converts to WebP to stay under 1MB base64 limits. Requires COMFYUI_HOST.

• download_output

  Download a single output file to a local path. Use list_outputs to get file info. Requires COMFYUI_HOST.

• execute_batchwrite action

  Execute multiple workflows in batch. Submits each workflow and waits for completion (polling). Optional concurrency and stop_on_error. Requires COMFYUI_HOST.

• execute_chainwrite action

  Execute a chain of workflows in sequence. Each step runs after the previous completes. Use inputFrom and outputTo to pass the output image from one step to the next (e.g. txt2img → upscale → img2img). Steps can use workflow JSON or saved workflow name. Prefer saved workflow name (string) for large workflows to avoid ENAMETOOLONG in some clients. Requires COMFYUI_HOST.

• execute_workflowwrite action

  Submit a ComfyUI workflow to run. Returns prompt_id. Use get_execution_status(prompt_id) to check result. Requires COMFYUI_HOST and ComfyUI running.

• execute_workflow_streamwrite action

  Execute workflow with streaming real-time progress updates. Requires WebSocket support. Returns result and progress event history. Use for monitoring execution progress. Requires COMFYUI_HOST and WebSocket connection.

• execute_workflow_syncwrite action

  Submit a ComfyUI workflow and wait until execution completes with real-time progress (WebSocket if available, polling fallback). Returns prompt_id, status (completed/failed/timeout), and outputs. When timeout_ms is omitted, uses recommended_timeout_ms from get_system_resources (higher on MPS/Apple). Use when you need the result before continuing. Requires COMFYUI_HOST.

• finalize_workflow

  Get the workflow JSON for a dynamic workflow (same as get_workflow_json). Use with execute_workflow or save_workflow.

• get_error_details

  Get full error details for a prompt (node_id, exception_type, exception_message, full traceback). Use when execute_workflow_sync failed or get_execution_status shows errors. Returns structured errors from ComfyUI history status.messages. Requires COMFYUI_HOST.

• get_execution_progress

  Get real-time execution progress for a prompt (WebSocket if available, polling fallback). Returns status, current_node, progress%, queue_position, and outputs. Requires COMFYUI_HOST.

• get_execution_status

  Get execution status and outputs for a prompt. Returns status, image filenames, and view URLs. Requires COMFYUI_HOST.

• get_generation_recommendations

  Get recommendations for image generation: system resources (max resolution, model size, batch) and, if the user prompt suggests text/letters in the image, advice on models and settings. Many base models (SD 1.5, SD XL) render text poorly; FLUX, SD 3, or checkpoints trained for text work better. Call when planning a txt2img or img2img workflow; pass the user's image description as prompt to get tex

• get_history

  Get ComfyUI execution history (GET /history) without prompt_id. Returns last N prompts with prompt_id, status, outputs (filenames), elapsed. Use when execute_workflow_sync did not return prompt_id (e.g. WebSocket timeout) to find the latest run and its outputs. Requires COMFYUI_HOST.

• get_last_output

  Get info for the most recent prompt that has image output (skips failed prompts). Use when prompt_id was lost (e.g. execute_workflow_sync timed out). Returns prompt_id, filename, subfolder, view_url. Then use download_by_filename to save the file. Requires COMFYUI_HOST.

• get_model_info

  Get info for a model by name and type. Returns name, type, path; null if not found. Requires COMFYUI_HOST.

• get_node_info

  Get full node information for a ComfyUI node by its class name. Uses live ComfyUI when COMFYUI_HOST is set, otherwise knowledge base.

• get_node_inputs

  Get detailed input definitions for a node (required and optional). Uses live ComfyUI if available, otherwise knowledge base.

• get_node_outputs

  Get output types and names for a node. Uses live ComfyUI if available, otherwise knowledge base.

• get_system_resources

  Get ComfyUI station resources (GPU/VRAM/RAM) and recommendations for model size, resolution, and batch size. Returns flux_ready (FLUX needs ~12GB+ VRAM) and platform_hints (e.g. Apple Silicon: M-Flux, ComfyUI-MLX). Call this first before building or executing workflows to avoid OOM. Requires COMFYUI_HOST.

• get_workflow_json

  Get the current workflow JSON for a dynamic workflow (for execute_workflow or save_workflow).

• get_workflow_models

  Extract required models from a workflow (loader nodes: CheckpointLoaderSimple, LoraLoader, VAELoader, ControlNetLoader, UpscaleModelLoader, etc.). Returns list of { name, type, nodeId, nodeClass, inputName }. No ComfyUI connection needed.

• insert_macrowrite action

  Insert a macro (sub-workflow) into a dynamic workflow. Connects macro input ports to existing nodes. Returns nodeIdMap and outputPorts so you can connect macro outputs. Use workflow_id from create_workflow.

• install_custom_node

  Install one or more custom nodes via ComfyUI-Manager cm-cli (e.g. ComfyUI-Blip, WAS-Node-Suite). Requires COMFYUI_PATH and ComfyUI-Manager installed in custom_nodes. ComfyUI-Manager cm-cli requires Python package "rich" (pip install rich in your ComfyUI Python environment). Restart ComfyUI after install to load new nodes.

• install_model

  Download and install a model (checkpoint, LoRA, VAE, etc.) by URL. Requires COMFYUI_PATH. Uses comfy-cli if available (pip install comfy-cli), otherwise fetches the file directly. model_type: checkpoint, lora, vae, controlnet, clip, embeddings, hypernetwork, upscale_models, clip_vision, unet, diffusers.

• interrupt_execution

  Stop the currently running workflow on ComfyUI. Optionally pass prompt_id to interrupt only that prompt. If cleanup_after_ms is set (and prompt_id given), after interrupt the tool will poll the queue and remove the prompt from queue if it is still there (frees GPU for next job). Requires COMFYUI_HOST.

• list_macros

  List available workflow macros (built-in sub-workflows). Returns id, name, description, inputs, outputs.

• list_models

  List models available on the ComfyUI server (from object_info). Optionally filter by type: checkpoint, lora, vae, controlnet, upscale, embedding, clip. Requires COMFYUI_HOST.

• list_node_categories

  List all node categories from live ComfyUI and knowledge base (merged, unique).

• list_node_types

  List ComfyUI node types from the knowledge base. Optionally filter by category or priority.

• list_outputs

  List all output files (images, gifs) for a completed prompt. Returns prompt_id, node_id, type, filename, url. Requires COMFYUI_HOST.

• list_plugins

  List loaded plugins (from plugins/*/plugin.json) and counts of macros/templates contributed by each.

• list_queue

  List current ComfyUI queue (running and pending prompts). Requires COMFYUI_HOST.

• list_saved_workflows

  List saved workflows (names and paths) from workflows/ directory.

• list_templates

  List available workflow template ids (e.g. txt2img). No ComfyUI connection needed.

• load_workflow

  Load a saved workflow by name (from workflows/<name>.json) or by path. Returns workflow JSON for use with execute_workflow or save_workflow.

• prepare_image_for_workflow

  Fetch the first output image from a completed prompt and upload it to ComfyUI input folder. Returns the filename to use in LoadImage for a follow-up workflow (e.g. image caption / verification). Use after get_execution_status confirms the prompt finished with image output. Requires COMFYUI_HOST.

• reload_comfyui

  Restart ComfyUI so that newly installed custom nodes are loaded, then optionally sync them to the knowledge base. Requires COMFYUI_PATH (ComfyUI installation directory) and uses COMFYUI_HOST for the port. Kills the process on the ComfyUI port and starts main.py from COMFYUI_PATH. After restart, call sync_nodes_to_knowledge to pick up custom nodes (or set sync_after_restart to true).

• reload_plugins

  Reload plugins from plugins/*/plugin.json and refresh macro registry.

• remove_nodewrite action

  Remove a node from a dynamic workflow. Does not fix references (validation will report dangling refs).

• save_workflow

  Save a workflow JSON to file (workflows/<name>.json). Returns path. Use after build_workflow to persist for later load_workflow or execute_workflow.

• search_nodes

  Search nodes by query string and optional filters (category, input_type, output_type). Searches both live ComfyUI and knowledge base; live overrides KB for same class.

• set_node_input

  Set a literal input on a node in a dynamic workflow (overwrites existing value or link).

• suggest_nodes

  Suggest ComfyUI nodes for a task (search by description/use_cases) or by output type they produce.

• suggest_template_for_checkpoint

  Suggest workflow template (txt2img_flux or txt2img) from checkpoint filename. FLUX checkpoints (e.g. flux1-dev-fp8.safetensors) use txt2img_flux; SD XL / SD 1.5 use txt2img. Call before build_workflow when the user did not specify a template.

• sync_nodes_to_knowledge

  Sync node definitions from running ComfyUI to the knowledge base. Adds only nodes that are not already in base-nodes.json. Creates knowledge/ if missing (or set COMFYUI_KNOWLEDGE_DIR to point to the knowledge directory). Requires ComfyUI to be running.

• validate_template_params

  Validate that parameter values satisfy a workflow template (required params, types).

• validate_workflow

  Validate a dynamic workflow: checks that all node references exist and output indices are valid.

• Code scan52 source files scanned13/25
• –Live reliabilityno gateway calls yet and no remote to proben/a
• –Tool poisoningtools not inspected (local package is not executed); not countedn/a
• Auth qualitylocal package, no credentials required12/15
• Maintenancelast push 5 days ago15/15
• Maintainer identityregistry namespace matches repository owner; GitHub account older than a year8/10

Safety score

74/100

higher than 40% of 48,255 servers

Tools

60

the typical server has 7

Tools that change things

17%

typical: 0%. Fewer write tools means less an agent can break

GitHub stars

3

more than 80% of 28,688 servers

Downloads a week

102

more than 63% of 12,191 servers with a package

ComfyUI Builder: common questions

Is ComfyUI Builder MCP server safe?

Mostly: it is graded B (74/100). Read the ComfyUI Builder safety report

How do I install ComfyUI Builder?

It runs on your machine. Copy the Claude Code, Cursor, VS Code or Claude Desktop config from the install section.

Does ComfyUI Builder need an API key?

No secret keys are declared. It reads 3 settings from the environment.

Is ComfyUI Builder maintained?

The last commit was 42 days ago (2026-09-23). The latest release is v2.4.1.

What can I use instead of ComfyUI Builder?

Servers from other publishers that do the same job: Comfyui MCP server.

How does ComfyUI Builder compare with other MCP servers?

safety score 74/100 (higher than 40% of 48,255 servers); tools 60 (the typical server has 7); tools that change things 17% (typical: 0%. Fewer write tools means less an agent can break). Full comparison.