Debug Skill

"Debugging is twice as hard as writing the code in the first place." — Brian Kernighan

Systematically surface logic flaws, latent bugs, performance bottlenecks, security vulnerabilities, and test gaps in existing code. Bias heavily toward what recently changed — most bugs live in the delta, not the stable baseline.

Before Analyzing

1. Orient to the diff — ask for or examine: recent commits, staged changes, modified files. Fresh eyes on fresh code first.
2. Understand the intent — what is this code supposed to do? A bug is only a bug relative to expected behavior.
3. Identify the blast radius — where does this code touch? What depends on it?
4. Don't assume the symptom is the problem — the reported failure often points one layer away from the actual root cause.

Analysis Dimensions