Use the async SDK

Use AsyncMCPTestKit when the surrounding test is asynchronous. Await direct operations instead of creating another event loop.

python

import sys
from pathlib import Path

import pytest

from m3.async_api import AsyncMCPTestKit
from m3.types import StdioServer

pytestmark = pytest.mark.m3(suite_name="shipping")


@pytest.mark.asyncio
async def test_shipping_async() -> None:
    root = Path(__file__).parents[1]
    server = StdioServer(
        name="shipping",
        command=sys.executable,
        args=(str(root / "shipping_server.py"),),
        cwd=str(root),
    )
    async with AsyncMCPTestKit(env={}) as kit:
        async with kit.direct(server) as client:
            result = await client.call_tool(
                "shipping_quote", {"weight_kg": 2, "zone": "local"}
            )
    assert result.structured_content == {"amount": 9.0, "currency": "USD"}

Run from the first-test project:

m3 test -- tests/test_shipping_async.py

The pytest extra includes async test support. The client must close before its final trace is inspected, as in the synchronous API.

Use the async SDK ​

Use the async SDK