Systematic Debugging

# Systematic Debugging

Iron law: no fixes without root-cause investigation first.

## When to use
Test failures, production bugs, unexpected behavior, performance issues, build or integration failures — especially under time pressure.

## Four phases
1. Root cause investigation — read errors fully, reproduce, gather evidence, form a hypothesis.
2. Pattern analysis — compare working vs broken paths; find the smallest failing case.
3. Hypothesis and test — change one variable; confirm the cause.
4. Implementation — fix the cause, add regression coverage, verify.

Skip no phase. Symptom patches that leave the cause intact are failures.


Adapted from @obra's approach: https://github.com/obra/superpowers/tree/main/skills/systematic-debugging