How to install the MCP Python SDK

1#!/usr/bin/env python3
2"""A complete MCP server demonstrating all capability types."""
3
4from mcp.server.fastmcp import FastMCP
5
6# Create the MCP server
7mcp = FastMCP("my-mcp-server")
8
9
10# === TOOLS (model-controlled actions) ===
11
12@mcp.tool()
13async def hello(name: str) -> str:
14    """Greet someone by name."""
15    return f"Hello, {name}!"
16
17
18@mcp.tool()
19async def calculate(a: float, b: float, operation: str) -> str:
20    """Perform basic arithmetic.
21    
22    Args:
23        a: First number
24        b: Second number  
25        operation: One of 'add', 'subtract', 'multiply', 'divide'
26    """
27    ops = {
28        "add": a + b,
29        "subtract": a - b,
30        "multiply": a * b,
31        "divide": a / b if b != 0 else "Error: division by zero",
32    }
33    result = ops.get(operation, f"Unknown operation: {operation}")
34    return f"{a} {operation} {b} = {result}"
35
36
37@mcp.tool()
38async def search_files(pattern: str, directory: str = ".") -> str:
39    """Search for files matching a glob pattern.
40    
41    Args:
42        pattern: Glob pattern like '*.py' or '**/*.json'
43        directory: Directory to search in (default: current)
44    """
45    import glob
46    import os
47    
48    search_path = os.path.join(directory, pattern)
49    matches = glob.glob(search_path, recursive=True)
50    if not matches:
51        return f"No files found matching '{pattern}' in {directory}"
52    return "\n".join(matches[:50])  # Limit to 50 results
53
54
55# === RESOURCES (app-controlled data) ===
56
57@mcp.resource("config://app")
58async def get_app_config() -> str:
59    """Current application configuration."""
60    import json
61    return json.dumps({
62        "name": "my-mcp-server",
63        "version": "1.0.0",
64        "python": "3.12",
65    }, indent=2)
66
67
68# === PROMPTS (user-controlled templates) ===
69
70@mcp.prompt()
71async def debug_error(error_message: str, language: str = "Python") -> str:
72    """Help debug an error message."""
73    return (
74        f"I encountered this error in {language}:\n\n"
75        f"{error_message}\n\n"
76        f"Please explain what caused this error and provide a fix."
77    )
78
79
80if __name__ == "__main__":
81    mcp.run()