What problem does it solve? Engineers often ship code they cannot interrogate in production: logs are unstructured strings, metrics explode with high-cardinality labels, alerts fire on causes instead of symptoms, and debugging relies on guesswork. This Skill provides a disciplined framework for making systems answerable to arbitrary questions without redeploying. ## Core Features & Use Cases - Instrumentation guidance: Structured logging, wide canonical events, OpenTelemetry setup (including .NET/ASP.NET Core examples), distributed tracing with sampling strategies, and context propagation. - Metrics and SLO discipline: RED, USE, and Four Golden Signals methods, cardinality rules, histogram-based latency, plus SLI/SLO/error-budget design and SLO-burn alerting. - Production debugging workflow: A hypothesis-driven loop using wide events and traces to localize, compare, and verify fixes. - Use Case: When adding a new endpoint, use this Skill to wrap the operation in spans, emit one canonical event per request, define an SLO, and set symptom-based alerts on its burn rate. ## Quick Start Ask Claude to review this service's instrumentation and suggest what to log, trace, and measure following observability best practices.