vcdebug

# Debugging & System Investigation Comprehensive framework combining systematic debugging, root cause tracing, defense-in-depth validation, verification protocols, and system-level investigation (logs, CI/CD, databases, performance). ## Core Principle **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 before claiming success. ## When to Use **Code-level:** Test failures, bugs, unexpected behavior, build failures, integration problems **System-level:** Server errors, CI/CD pipeline failures, performance degradation, database issues, log analysis **Always:** Before claiming work complete ## Techniques ### 1. Systematic Debugging (`references/systematic-debugging.md`) Four-phase framework: Root Cause Investigation → Pattern Analysis → Hypothesis Testing → Implementation. Complete each phase before proceeding. No fixes without Phase 1. **Load when:** Any bug/issue requiring investigation and fix ### 2. Root Cause Tracing (`references/root-cause-tracing.md`) Trace bugs backward through call stack to find original trigger. Fix at source, not symptom. Includes `scripts/find-polluter.sh` for bisecting test pollution. **Load when:** Error deep in call stack, unclear where invalid data originated ### 3. Defense-in-Depth (`references/defense-in-depth.md`) Validate at every layer: Entry validation → Business logic → Environment guards → Debug instrumentation **Loa...