public final class Metrics

The server’s metrics: every Instrument by name, and the ones the server records about itself.

  private static final Counter ORDERS = Metrics.counter("orders.placed",
          "Orders accepted", "{order}");
  ...
  ORDERS.increment();

Asking for a name twice answers the same instrument, so a static field initialized in two classes, or a server restarted in one process, shares it. Asking for an existing name as a different kind is refused.

What reads them: the OTLP exporter, when the build enables OpenTelemetry; the management endpoint’s metrics and prometheus views; and the development MCP server. None of them is linked into a server whose build does not ask for it, and an instrument nothing reads costs its own recording and nothing more.

What the server records

Once enableServer has run – the generated entry point calls it when metrics are on – every request is measured in http.server.request.duration (milliseconds, by route template, method and status), and the server’s counters, the database pool, the task executors and the process’s memory are published as gauges.