ComfyUI Agent SKILL

Prerequisites: Install the CLI: pip install -U comfyui-skill-cli. The official local Comfy MCP is optional and should be connected using the official guide when MCP capabilities are needed. All shell commands must run from this project's root directory (where this SKILL.md is located).

[!IMPORTANT] Directory Sensitivity: The CLI reads config.json and data/ from the current directory. You MUST cd into the project root before running any command. Symptom: list returns [] or server status reports not found → you are in the wrong directory.

Quick Decision

• A matching registered workflow exists → use the CLI Execution Flow (Step 1-4). This is the default for repeated, batch, and latency-sensitive work.
• The request has no matching workflow, or requires live template/model/node discovery → use the official local Comfy MCP.
• The user supplies a raw workflow that needs real environment validation → use MCP validate_workflow; use CLI run --validate for a registered workflow.
• The user asks to install nodes, download models, restart, update, or switch versions → use MCP only after explaining the effect and getting confirmation.
• User says "generate image / draw a picture" → first inspect registered workflows; if none fit, discover a current MCP template instead of guessing a model name.
• User says "import workflow / add workflow" → comfyui-skill --json workflow import <path>
• User says "img2img / use this image" → first comfyui-skill --json upload <image>, then execute
• User says "inpainting / mask this area" → comfyui-skill --json upload <mask> --mask, then execute
• User says "show previous results" → comfyui-skill --json history list <id>
• User says "what failed / check job status" → comfyui-skill --json jobs list --status failed
• User says "which server has more VRAM" → comfyui-skill --json server stats --all
• User says "what nodes are available" → use MCP nodes for live ecosystem discovery; use comfyui-skill --json nodes list when only the CLI inventory is needed.
• User says "dry run / test without executing" → comfyui-skill --json run <id> --validate
• User says "open management UI" → python3 ./ui/open_ui.py

Core Concepts

• Skill ID: <server_id>/<workflow_id> (e.g., local/txt2img). If server is omitted, the default server is used.
• Schema: Each workflow has a schema.json that maps business parameter names (e.g., prompt, seed) to internal ComfyUI node fields. Never expose node IDs to the user.
• Server: One or more ComfyUI instances configured in config.json. Check health with server status.
• Two interfaces, one Skill: CLI is the efficient execution path for known workflows. Official MCP is the adaptive path for discovering and orchestrating the current ComfyUI ecosystem. They share the same business intent and must not submit the same job twice.

Official Local Comfy MCP

When the Agent host exposes the official Comfy MCP tools, call those tools directly. Start every MCP flow with server_info and use the live tool schemas instead of assuming parameters or tool availability.

When the host does not expose MCP tools but can run shell commands, use the included stdio bridge:

python ./scripts/comfy_mcp.py probe
python ./scripts/comfy_mcp.py tools
python ./scripts/comfy_mcp.py call search_templates --arguments '{"query":"background removal"}'

The bridge reads mcp_command, mcp_args, mcp_python, mcp_cwd, and mcp_env from the selected server in config.json. probe and tools are read-only. A call has the side effects of the named official tool.

Read references/comfy-mcp.md when the request needs MCP discovery, raw-workflow validation, template adaptation, job management, installation, lifecycle control, or partner models.

Routing invariants:

• Prefer CLI for a known <server_id>/<workflow_id>; MCP is not a mandatory extra hop.
• Prefer MCP when the answer depends on the currently installed templates, nodes, models, hardware, or official tool contract.
• For long MCP runs: run_workflow(wait=false) or run_template(wait=false) -> job(action="wait"|"status") -> fetch_outputs.
• Once either path returns a prompt_id, continue polling that path. Never fall back by submitting again.
• Never set confirm_spend=true without the user's explicit approval for that paid call.

Command Reference

Execution Flow

Step 1: Query Available Workflows

comfyui-skill --json list

Returns a JSON array of all enabled workflows with their parameters.

• required: true parameters → ask the user if not provided.
• required: false parameters → infer from context (e.g., seed = random number), or omit.
• Never expose node IDs; only use business parameter names (e.g., prompt, style).
• If multiple workflows match, pick the most relevant one or list candidates.

Step 2: Parameter Assembly

Assemble parameters into a JSON string. Example:

{"prompt": "A beautiful landscape, high quality, masterpiece", "seed": 40128491}

If critical parameters are missing, ask the user (e.g., "What visual style would you like?").

Step 3: Pre-flight Dependency Check

Always run before first execution of a workflow:

comfyui-skill --json deps check <server_id>/<workflow_id>

• If is_ready is true → proceed to Step 4.
• If is_ready is false:
  1. Present missing nodes and models to the user.
  2. If user agrees to install, run:

     comfyui-skill --json deps install <id> --repos '["https://github.com/repo1"]'
     

     Use source_repo URLs from the check report as --repos values.
  3. If needs_restart is true, inform the user to restart ComfyUI, then re-check.
  4. Missing models must be downloaded manually — tell the user which folder to place them in (e.g., checkpoints).

Step 4: Execute the Workflow

Note: JSON args must be wrapped in single quotes to prevent bash from parsing double quotes.

Choose the execution mode based on your environment:

Interactive mode: submit + status (recommended for chat)

Step 4a — Submit:

comfyui-skill --json submit <id> --args '{"prompt": "..."}'

Returns: {"status": "submitted", "prompt_id": "..."}. Tell the user generation has started.

Step 4b — Poll:

comfyui-skill --json status <prompt_id>

Status values: queued (with position) → running → success (with outputs) or error.

Polling pattern — critical for real-time feedback:

Each status call must be a separate tool invocation (a separate bash command). Do NOT write a shell loop. The correct pattern is:

1. Run status as a standalone bash command.
2. Read the returned JSON.
3. If queued or running: send a text message to the user with progress, then run status again.
4. If success: proceed to Step 5.
5. If error: report the error.

Non-interactive mode: one-shot blocking (for scripts/CI)

comfyui-skill --json run <id> --args '{"prompt": "..."}'

Blocks until finished. Returns the same result format as status with success.

Step 5: Present Results

On success, the result contains an outputs array with file references (filename, subfolder, type). Use your native capabilities to present the files to the user (e.g., image preview, file path).

Workflow Import

When the user wants to add new workflows (not execute existing ones):

comfyui-skill --json workflow import <json_path>

• Supports both API format and editor format (auto-detected, auto-converted).
• Automatically generates schema.json with smart parameter extraction.
• After import, check dependencies before first execution.

For bulk import from ComfyUI server or local folders, see references/workflow-import.md.

Troubleshooting

1. ComfyUI Offline: Run comfyui-skill --json server status. If offline, ask the user to start ComfyUI.
2. Workflow Not Found: Run comfyui-skill --json list to see available workflows. If missing, the user needs to import it first.
3. Parameter Format Error: Ensure --args is valid JSON wrapped in single quotes.
4. Cloud Node Unauthorized: Workflow uses cloud API nodes (Kling, Sora, etc.). Guide user to: (1) Generate an API Key at https://platform.comfy.org, (2) Open Web UI → Server Settings → fill in "ComfyUI API Key".