Context A microservices architecture spanning five Node.js services has no observability. Debugging latency issues requires manually correlating logs across services. The Problem There is no trace correlation between services, making it impossible to follow a single request through the entire system. Constraints Instrument each service with the OpenTelemetry Node.js SDK. Propagate trace context via HTTP headers (W3C TraceContext). Export spans to Jaeger or Zipkin. Add custom span attributes for business context (userId, orderId). Expected Deliverable A Node.js multi-service setup fully instrumented with OpenTelemetry, propagating trace context across HTTP calls and exporting spans to a distributed tracing backend.