ComfyUI MCP Server

Instructions

    Args:
        prompt_id: The prompt ID from submit_workflow()
        output_node_id: Node ID that produced the image

    Returns the image if available, or error message.
    

Implementation Reference

• src/comfy_mcp_server/tools/execution.py:205-252 (handler)

  The handler function for the 'get_result_image' tool. It retrieves the prompt history from ComfyUI, verifies completion, extracts the image filename from the output node, downloads the image data, and returns it as an MCP Image object.

  @mcp.tool()
  def get_result_image(
      prompt_id: str = Field(description="Prompt ID"),
      output_node_id: str = Field(description="Output node ID"),
      ctx: Context = None,
  ):
      """Get the result image from a completed prompt.
  
      Args:
          prompt_id: The prompt ID from submit_workflow()
          output_node_id: Node ID that produced the image
  
      Returns the image if available, or error message.
      """
      if ctx:
          ctx.info(f"Getting result: {prompt_id}")
  
      try:
          history = comfy_get(f"/history/{prompt_id}")
          if prompt_id not in history:
              return "Prompt not found in history"
  
          entry = history[prompt_id]
          status = entry.get("status", {})
  
          if not status.get("completed"):
              return "Prompt not yet completed"
  
          outputs = entry.get("outputs", {})
          if output_node_id not in outputs:
              return f"No output from node {output_node_id}"
  
          images = outputs[output_node_id].get("images", [])
          if not images:
              return "No images in output"
  
          # Download image
          url = get_file_url(settings.comfy_url, images[0])
          from ..api import download_file
  
          image_data = download_file(url)
          if image_data:
              return Image(data=image_data, format="png")
          return "Failed to download image"
  
      except Exception as e:
          return f"Error: {e}"

• src/comfy_mcp_server/tools/__init__.py:28-28 (registration)

  Registration call for execution tools, including 'get_result_image', within the register_all_tools function.

  register_execution_tools(mcp)

• src/comfy_mcp_server/__init__.py:92-92 (registration)

  Top-level registration of all tools by calling register_all_tools(mcp), which indirectly registers 'get_result_image'.

  register_all_tools(mcp)

• src/comfy_mcp_server/tools/execution.py:206-210 (schema)

  Input schema defined via Pydantic Field descriptions for prompt_id and output_node_id parameters.

  def get_result_image(
      prompt_id: str = Field(description="Prompt ID"),
      output_node_id: str = Field(description="Output node ID"),
      ctx: Context = None,
  ):