ComfyUI MCP Server

Instructions

    Args:
        node_name: Node class name (e.g., 'RemoteCheckpointLoader_fal')

    Returns node information including:
    - input: Required and optional inputs with types
    - output: Output types
    - category: Node category
    - description: What the node does

    Use this to understand how to configure a node in a workflow.
    

Implementation Reference

• src/comfy_mcp_server/tools/discovery.py:52-85 (handler)

  MCP tool handler for get_node_info. Fetches node details from ComfyUI /object_info endpoint, parses with NodeInfo model, handles errors.

  @mcp.tool()
  def get_node_info(
      node_name: str = Field(description="Exact node class name"),
      ctx: Context = None,
  ) -> dict:
      """Get detailed info about a node.
  
      Args:
          node_name: Node class name (e.g., 'RemoteCheckpointLoader_fal')
  
      Returns node information including:
      - input: Required and optional inputs with types
      - output: Output types
      - category: Node category
      - description: What the node does
  
      Use this to understand how to configure a node in a workflow.
      """
      if ctx:
          ctx.info(f"Fetching info for: {node_name}")
  
      try:
          result = comfy_get(f"/object_info/{node_name}")
          if node_name in result:
              data = result[node_name]
              data["name"] = node_name  # Ensure name is set
              info = NodeInfo(**data)
              return info.model_dump()
          return ErrorResponse.not_found(
              f"Node '{node_name}'",
              suggestion="Use list_nodes() to see available nodes",
          ).model_dump()
      except Exception as e:
          return ErrorResponse.unavailable(str(e)).model_dump()

• src/comfy_mcp_server/models.py:79-92 (schema)

  Pydantic model defining the structure and validation for node information output by the tool.

  class NodeInfo(BaseModel):
      """Information about a ComfyUI node from /object_info."""
  
      name: str
      display_name: str | None = None
      description: str | None = None
      category: str | None = None
      input: NodeInput = Field(default_factory=NodeInput)
      output: list[str] = Field(default_factory=list)
      output_name: list[str] = Field(default_factory=list)
      output_node: bool = False
      deprecated: bool = False
      experimental: bool = False

• src/comfy_mcp_server/tools/__init__.py:22-28 (registration)

  Registration function that calls register_discovery_tools(mcp), which defines and registers the get_node_info tool.

  def register_all_tools(mcp):
      """Register all tools with the MCP server."""
      register_system_tools(mcp)
      register_discovery_tools(mcp)
      register_workflow_tools(mcp)
      register_execution_tools(mcp)

• src/comfy_mcp_server/api.py:247-250 (helper)

  Helper function in API module that performs the core API call used by the tool handler.

  def get_node_info(node_name: str) -> dict:
      """Get info for a specific node."""
      return comfy_get(f"/object_info/{node_name}")

• src/comfy_mcp_server/models.py:72-77 (schema)

  Pydantic model for node input schema used within NodeInfo.

  class NodeInput(BaseModel):
      """Node input specification."""
  
      required: dict[str, Any] = Field(default_factory=dict)
      optional: dict[str, Any] = Field(default_factory=dict)