Python MCP server

1"""Main entry point for the MCP Server Actor."""
2
3import os
4
5from apify import Actor
6from fastmcp import FastMCP
7
8# Initialize the Apify Actor environment
9# This call configures the Actor for its environment and should be called at startup
10
11
12def get_server() -> FastMCP:
13    """Create an MCP server with implementation details."""
14    server = FastMCP('python-mcp-empty', '1.0.0')
15
16    @server.tool()  # type: ignore[misc]
17    def add(a: float, b: float) -> dict:
18        """Add two numbers together and return the sum with structured output.
19
20        Args:
21            a: First number to add
22            b: Second number to add
23
24        Returns:
25            Dictionary with the sum result and structured output
26        """
27        # Note: We can't await here in sync context, so charging happens in async wrapper
28        sum_result = a + b
29        structured_content = {
30            'result': sum_result,
31            'operands': {'a': a, 'b': b},
32            'operation': 'addition',
33        }
34
35        return {
36            'type': 'text',
37            'text': f'The sum of {a} and {b} is {sum_result}',
38            'structuredContent': structured_content,
39        }
40
41    @server.resource(uri='https://example.com/calculator', name='calculator-info')  # type: ignore[misc]
42    def calculator_info() -> str:
43        """Get information about the calculator service."""
44        return 'This is a simple calculator MCP server that can add two numbers together.'
45
46    return server
47
48
49async def main() -> None:
50    """Run the MCP Server Actor.
51
52    This function:
53    1. Initializes the Actor
54    2. Creates and configures the MCP server
55    3. Starts the HTTP server with Streamable HTTP transport
56    4. Handles MCP requests
57    """
58    await Actor.init()
59
60    # Get port from environment or default to 3000
61    port = int(os.environ.get('APIFY_CONTAINER_PORT', '3000'))
62
63    server = get_server()
64
65    try:
66        Actor.log.info('Starting MCP server with FastMCP')
67
68        # Start the FastMCP server with HTTP transport
69        # This starts the server on the specified port and handles MCP protocol messages
70        await server.run_http_async(
71            host='0.0.0.0',  # noqa: S104 - Required for container networking
72            port=port,
73        )
74    except KeyboardInterrupt:
75        Actor.log.info('Shutting down server...')
76    except Exception as error:
77        Actor.log.error(f'Server failed to start: {error}')
78        raise
79
80
81if __name__ == '__main__':
82    import asyncio
83
84    asyncio.run(main())