Individual skill

systematic-debugging

You MUST use this whenever something is broken, before proposing or making any fix, including quick fixes and when the user is in a hurry: a bug, a failing or red test, a build or CI failure, a crash, a performance problem, unexpected behavior. Finds the root cause in four phases (investigate, compare, test one hypothesis, fix with a failing test first) instead of guessing, and stops after three failed fixes to question the design. Not for writing new features.

cli-tool/components/skills/development/systematic-debugging/SKILL.md

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Repository stars (not skill ratings): 33,193
Repository last updated: Nov 7, 2026
License: MIT

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# Systematic Debugging

Guessing at fixes feels fast and is slow. Each guess that half-works hides
the real cause a little deeper, and the third patch usually breaks
something the first one touched. This skill makes you find out *why*
before you change anything.

## The Iron Law

```
NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST
```

If you have not finished Phase 1, you cannot propose a fix. Not a "quick