Comprehensive practitioner guide to debugging, logging, error handling, and production observability (2026): Agans' nine rules, delta debugging, reproducibility imperative, correlation/trace IDs, OpenTelemetry (CNCF graduated May 11 2026), structured logging (slog/Pino/Serilog/structlog), four observability signals (logs/metrics/traces/profiling), eBPF zero-instrumentation telemetry, SLO-based burn-rate alerting, resilience patterns (retries with jitter, circuit breakers, bulkheads), distributed debugging, AI debugging limitations (OpenRCA 11–36%), and language-specific patterns for Python, TypeScript/JavaScript, and Go.
