systematic-debugginglisted

# Systematic Debugging Find and fix bugs by following a strict process: no fixes without root cause first. **Why this matters:** Random fixes feel faster but often introduce new bugs and leave the original cause in place. A few minutes of real investigation—reproduce, trace, hypothesize—usually leads to one right fix instead of a long chain of patches. It works the same whether you’re in a Node app, a Python script, or a distributed system: understand, then change. ## Core Principle **NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST.** Symptom fixes waste time and introduce new bugs. If you have not completed Phase 1, you may not propose fixes. ## When to Activate - User reports a bug, error, or "it doesn't work" - Test failures, build failures, or integration issues - Unexpected behavior or performance problems - User asks to "debug", "find the bug", or "why does X happen" **Use especially when:** Under time pressure, "one quick fix" seems obvious, you've already tried multiple fixes, or you don't fully understand the issue. Do not skip for "simple" bugs — simple bugs have root causes too. ## The Four Phases Complete each phase before proceeding to the next. ### Phase 1: Root cause investigation **Before attempting ANY fix:** 1. **Read error messages and stack traces** - Do not skip past errors or warnings. Note line numbers, file paths, and error codes. - They often contain the exact cause or the failing component. 2. **Reproduce consistently — the feedbac