Hello MCP - Your First Server¶

from mcp.server import Server, NotificationOptions
from mcp.server.models import InitializationOptions
import mcp.server.stdio
import mcp.types as types

# Create a server instance
server = Server("hello-mcp")

@server.list_tools()
async def handle_list_tools() -> list[types.Tool]:
    """List available tools."""
    return [
        types.Tool(
            name="say_hello",
            description="Say hello in different languages",
            inputSchema={
                "type": "object",
                "properties": {
                    "name": {
                        "type": "string",
                        "description": "Name to greet"
                    },
                    "language": {
                        "type": "string",
                        "enum": ["english", "spanish", "french", "japanese"],
                        "description": "Language for greeting"
                    }
                },
                "required": ["name"]
            }
        ),
        types.Tool(
            name="calculate",
            description="Perform basic arithmetic",
            inputSchema={
                "type": "object",
                "properties": {
                    "operation": {
                        "type": "string",
                        "enum": ["add", "subtract", "multiply", "divide"],
                        "description": "Math operation"
                    },
                    "a": {
                        "type": "number",
                        "description": "First number"
                    },
                    "b": {
                        "type": "number",
                        "description": "Second number"
                    }
                },
                "required": ["operation", "a", "b"]
            }
        )
    ]

@server.call_tool()
async def handle_call_tool(
    name: str, arguments: dict | None
) -> list[types.TextContent | types.ImageContent | types.EmbeddedResource]:
    """Execute a tool and return results."""

    if name == "say_hello":
        user_name = arguments.get("name", "friend")
        language = arguments.get("language", "english")

        greetings = {
            "english": f"Hello, {user_name}!",
            "spanish": f"¡Hola, {user_name}!",
            "french": f"Bonjour, {user_name}!",
            "japanese": f"こんにちは、{user_name}さん!"
        }

        return [types.TextContent(
            type="text",
            text=greetings.get(language, greetings["english"])
        )]

    elif name == "calculate":
        operation = arguments.get("operation")
        a = arguments.get("a", 0)
        b = arguments.get("b", 0)

        if operation == "add":
            result = a + b
        elif operation == "subtract":
            result = a - b
        elif operation == "multiply":
            result = a * b
        elif operation == "divide":
            if b == 0:
                raise ValueError("Division by zero!")
            result = a / b
        else:
            raise ValueError(f"Unknown operation: {operation}")

        return [types.TextContent(
            type="text",
            text=f"Result: {result}"
        )]

    else:
        raise ValueError(f"Unknown tool: {name}")

async def run():
    """Run the MCP server."""
    async with mcp.server.stdio.stdio_server() as (read_stream, write_stream):
        await server.run(
            read_stream,
            write_stream,
            InitializationOptions(
                server_name="hello-mcp",
                server_version="0.1.0",
                capabilities=server.get_capabilities(
                    notification_options=NotificationOptions(),
                    experimental_capabilities={},
                ),
            ),
        )

if __name__ == "__main__":
    import asyncio
    asyncio.run(run())

import asyncio
from mcp import ClientSession, StdioServerParameters
from mcp.client.stdio import stdio_client

async def test_server():
    """Test the Hello MCP server."""
    server_params = StdioServerParameters(
        command="python",
        args=["server.py"]
    )

    async with stdio_client(server_params) as (read, write):
        async with ClientSession(read, write) as session:
            # Initialize connection
            await session.initialize()

            # List available tools
            tools = await session.list_tools()
            print("Available tools:")
            for tool in tools:
                print(f"  - {tool.name}: {tool.description}")

            # Test say_hello
            print("\nTesting say_hello:")
            result = await session.call_tool(
                "say_hello",
                arguments={"name": "World", "language": "spanish"}
            )
            print(f"  Result: {result.content[0].text}")

            # Test calculate
            print("\nTesting calculate:")
            result = await session.call_tool(
                "calculate",
                arguments={"operation": "multiply", "a": 7, "b": 6}
            )
            print(f"  Result: {result.content[0].text}")

if __name__ == "__main__":
    asyncio.run(test_server())