# Bisect Regression

> Bisect the Regression

- Skill: `archive228/bisect-regression` (Agent Skill)
- Install (CLI): `npx skillmds@latest add archive228/bisect-regression`
- Raw SKILL.md: https://api.skillmd.com/api/skills/archive228/bisect-regression/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: archive228 (https://skillmd.com/u/archive228)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/archive228/bisect-regression

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# Bisect the Regression
1. Find a known-good commit and a known-bad one. Confirm both by actually checking out and testing.
2. `git bisect start; git bisect bad <bad>; git bisect good <good>`.
3. At each step, run the SMALLEST test that distinguishes good from bad. Mark `git bisect good/bad`.
4. When git names the first bad commit, read its diff. The bug is in those lines — don't guess elsewhere.
5. `git bisect reset`. Report: the commit, the line, the one-sentence cause.
Automate it: `git bisect run ./repro.sh` if you have a script that exits non-zero on the bug.