Usage with `FastMCP`¶

1. Install `lite-bootstrap[fastmcp-all]`:¶

uvpippoetry

uv add "lite-bootstrap[fastmcp-all]"

pip install "lite-bootstrap[fastmcp-all]"

poetry add "lite-bootstrap[fastmcp-all]"

2. Define bootstrapper config and build your application:¶

from fastmcp import FastMCP
from lite_bootstrap import FastMcpBootstrapper, FastMcpConfig


bootstrapper_config = FastMcpConfig(
    service_name="microservice",
    service_version="2.0.0",
    service_environment="test",
    sentry_dsn="https://testdsn@localhost/1",
    prometheus_metrics_path="/custom-metrics/",
    health_checks_path="/custom-health/",
    logging_buffer_capacity=0,
)
bootstrapper = FastMcpBootstrapper(bootstrap_config=bootstrapper_config)
application: FastMCP = bootstrapper.bootstrap()


@application.tool
def greet_person(person_name: str) -> str:
    return f"Hello, {person_name}!"

Logging¶

The per-MCP-message access log is off by default, matching FastAPI and Litestar. Turn it on explicitly:

FastMcpConfig(
    service_name="microservice",
    fastmcp_logging_middleware_enabled=True,
)

Enabled, each message is logged with its method, source and type, plus duration in nanoseconds. A message that raises is logged at exception level and the exception is re-raised.

Set health_checks_enabled=False to omit the health route.

Metrics¶

With the fastmcp-metrics extra installed, the registry is served at prometheus_metrics_path, every application application.http_app() builds counts its requests by route, and every tool call is counted and timed. See the configuration reference for the metric names and parameters.

Tracing¶

With opentelemetry_endpoint set (and the fastmcp-otl extra installed), every ASGI application application.http_app() builds, including the one application.run(transport="http") builds, is wrapped in OpenTelemetry's ASGI middleware. Each request produces a server span named after its route, such as POST /mcp or GET /health/, with the route in http.route. A request to an unknown path produces a span named after the HTTP method alone, without http.route.

The metrics path, the health-check path (unless opentelemetry_generate_health_check_spans is on) opentelemetry_excluded_urls and OTEL_PYTHON_STARLETTE_EXCLUDED_URLS produce no spans. An application already instrumented by StarletteInstrumentor is left as is, so no request is traced twice.

Teardown is wired through FastMCP's provider lifecycle: bootstrapper.teardown() runs automatically when the FastMCP server's ASGI lifespan shuts down (i.e. when the application that serves application.http_app() shuts down).

Read more about available configuration options here.

Usage with FastMCP¶

1. Install lite-bootstrap[fastmcp-all]:¶