Prefect MCP Server

Instructions

Implementation Reference

• src/mcp_prefect/variable.py:50-73 (handler)

  The core handler function for the 'get_variable' MCP tool. It uses the Prefect client to read the variable by name and returns its details as JSON text content or an error message.

  @mcp.tool
  async def get_variable(
      name: str,
  ) -> List[Union[types.TextContent, types.ImageContent, types.EmbeddedResource]]:
      """
      Get a variable by name.
      
      Args:
          name: The variable name
          
      Returns:
          Variable details or error message if not found
      """
      try:
          async with get_client() as client:
              variable = await client.read_variable_by_name(name)
              
              if variable is None:
                  return [types.TextContent(type="text", text=json.dumps({"error": f"Variable '{name}' not found"}, indent=2))]
              
              return [types.TextContent(type="text", text=json.dumps(variable.model_dump(), indent=2, default=str))]
      except Exception as e:
          return [types.TextContent(type="text", text=json.dumps({"error": str(e)}, indent=2))]

• src/mcp_prefect/main.py:70-72 (registration)

  The import statement that loads the variable.py module, triggering registration of the get_variable tool via its @mcp.tool decorator.

  if APIType.VARIABLE.value in apis:
      info("Loading Variable API...")
      from . import variable

• src/mcp_prefect/variable.py:54-62 (schema)

  Docstring describing the input schema (name: str) and output (list of TextContent with JSON). The actual schema is inferred from the function signature by FastMCP.

  """
  Get a variable by name.
  
  Args:
      name: The variable name
      
  Returns:
      Variable details or error message if not found
  """