Prefect MCP Server

Instructions

Implementation Reference

• src/mcp_prefect/variable.py:160-190 (handler)

  The handler function for the 'delete_variable' tool. It checks if the variable exists, deletes it using the Prefect client if it does, and returns appropriate success or error messages in MCP TextContent format. The @mcp.tool decorator registers this function as an MCP tool.

  @mcp.tool
  async def delete_variable(
      name: str,
  ) -> List[Union[types.TextContent, types.ImageContent, types.EmbeddedResource]]:
      """
      Delete a variable by name.
      
      Args:
          name: The variable name
          
      Returns:
          Confirmation message or error
      """
      try:
          async with get_client() as client:
              # Check if variable exists first
              existing_variable = await client.read_variable_by_name(name)
              if existing_variable is None:
                  return [types.TextContent(type="text", text=json.dumps({"error": f"Variable '{name}' not found"}, indent=2))]
              
              await client.delete_variable_by_name(name)
              
              return [types.TextContent(type="text", text=json.dumps({
                  "message": f"Variable '{name}' deleted successfully"
              }, indent=2))]
      except ObjectNotFound:
          return [types.TextContent(type="text", text=json.dumps({
              "error": f"Variable '{name}' not found"
          }, indent=2))]
      except Exception as e:
          return [types.TextContent(type="text", text=json.dumps({"error": str(e)}, indent=2))]

• src/mcp_prefect/server.py:6-6 (registration)

  Creation of the FastMCP server instance 'mcp' to which tools are registered via decorators.

  mcp = FastMCP(f"MCP Prefect {__version__}")

• src/mcp_prefect/main.py:72-72 (registration)

  Import of the variable module which triggers the registration of variable-related tools (including delete_variable) via their @mcp.tool decorators.

  from . import variable