Calling Server Tools

Now to trigger tool calls in the server from your client! Again, you'll be using asynchronous operations to ensure that nothing breaks or freezes while waiting for other operations to complete.

This exercise is part of the course

Introduction to Model Context Protocol (MCP)

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Exercise instructions

Call the tool with the tool_name and arguments parameters specified by the user; ensure that the call pauses to wait for the server to respond using the appropriate Python keyword.
Extract and print the text content of the server response.
Run the "convert_currency" tool with a set of valid parameters (use whatever values and currencies you wish here).

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

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

async def call_mcp_tool(tool_name: str, arguments: dict) -> str:
    params = StdioServerParameters(
        command=sys.executable,
        args=["currency_server.py"],
    )

    async with stdio_client(params) as (reader, writer):
        async with ClientSession(reader, writer) as session:
            await session.initialize()

            # Call the currency conversion tool
            result = ____ ____(tool_name, arguments)

            # Extract and print the text content of the server response
            text_content = result.____[0].____

            print(f"Conversion Result: {text_content}")
            return text_content

# Run the "convert_currency" tool
asyncio.run(
    call_mcp_tool("convert_currency",
                  {"amount": 250.0, "from_currency": "USD", "to_currency": "EUR"})
)

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