@mcpose/otel

@mcpose/otel@0.1.0 adapts onTelemetry to an OpenTelemetry tracer. Your application installs and configures the SDK, exporter, and sampler.

Install

npm install mcpose@^3 @modelcontextprotocol/sdk@^1.17.0 @mcpose/otel@0.1.0 @opentelemetry/api@^1

Connect a tracer

import { createBackendClient, startProxy } from 'mcpose';
import { createOtelTelemetry } from '@mcpose/otel';
import { trace } from '@opentelemetry/api';

const upstream = await createBackendClient({ command: 'node', args: ['./server.mjs'] });
await startProxy(upstream, {
  name: 'monitored-proxy',
  onTelemetry: createOtelTelemetry(trace.getTracer('mcpose-gateway')),
});

Span semantics

One completed span is emitted per TelemetryEvent. A tool_call span is backdated using duration_ms and ended immediately; a backend_degraded span is a zero-duration marker. Spans are unparented and never enter the active context. Correlate through mcpose.request.id, mcpose.session.id, mcpose.identity.sub, and mcpose.proxy.* attributes rather than expecting a nested upstream trace. A throwing telemetry sink does not fail the proxied call. The adapter exports traces, not a metrics pipeline, and it does not automatically instrument prompt fetches.