taku-debug — 4-Phase Root Cause Investigation

Random fixes create new bugs. Systematic investigation finds root causes. This skill merges the best of Superpowers' systematic debugging with gstack's investigate workflow into a unified 4-phase process.

Rule labels: [IRON LAW] means a non-negotiable correctness constraint. [GUIDANCE] means a strong default that may adapt when context justifies it.

When to Use This Skill

Use taku-debug when:

• the VERIFY phase fails and the failure path is not yet understood
• the user reports broken behavior, a regression, or an intermittent issue
• you need to explain why something is failing before proposing the fix

Do not use taku-debug just to run routine verification. Run the repo's normal checks first. Enter this skill when those checks fail or when production behavior is already broken.

The Iron Law

[IRON LAW] NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST.