debug

# Debug Comprehensive debugging across the four disciplines you work in: software, data engineering, devops, analytics. Systematic investigation, root-cause-first, defense-in-depth, and verified-before-claimed-done. ## Iron law ``` NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST ``` Random fixes waste time and create new bugs. Find root cause → fix at source → validate at every layer → verify with fresh evidence before claiming done. ## When to use | Surface | Triggers | |---|---| | **Software** | test failures, bugs, exceptions, build failures, integration regressions | | **System** | server 5xx, CI/CD pipeline failures, deploy failures, performance degradation, OOM, timeouts | | **Data pipeline** | DAG failures, dbt test failures, source-freshness alerts, schema drift, late/missing data, row-count anomalies, lineage breaks | | **Infrastructure** | K8s pod CrashLoopBackOff, secret rotation issues, env-var mismatch across environments, IaC drift, image pull errors, networking/policy denial | | **Analytics / BI** | dashboards showing wrong numbers, metric drift, exposure-aware refresh failures, BI cache staleness, broken charts after model changes | | **Always** | before claiming work complete | ## Techniques (load on demand) ### Code-level | # | Reference | Load when | |---|---|---| | 1 | `references/systematic-debugging.md` | Any bug/issue requiring investigate→fix loop | | 2 | `references/root-cause-tracing.md` | Error deep in call stack, unclear where bad data ori...