What problem does it solve? Production Python applications often lack the visibility needed to answer what broke, where, and why without redeploying code. This Skill provides patterns for structured logging, metrics collection, and distributed tracing so you can diagnose production issues quickly. ## Core Features & Use Cases - Structured Logging with structlog: Emit JSON logs with consistent fields, semantic log levels, and correlation IDs threaded through request chains via contextvars and middleware. - Prometheus Metrics: Track the four golden signals (latency, traffic, errors, saturation) with bounded label cardinality to avoid metric explosion. - Distributed Tracing: Set up OpenTelemetry spans with OTLP export to trace requests across services. - Use Case: When a payment endpoint starts failing intermittently in production, use correlation IDs to trace a single request across services, query structured logs for error context, and check latency histograms to pinpoint the slow dependency. ## Quick Start Add structured logging with structlog and a correlation ID middleware to my FastAPI application.