Andersonlimahw Git Bisect AI
Find the commit that broke it — without reading 500 commits manually.
Quick Start
/git-bisect-ai — interactive bisect session
/git-bisect-ai --auto "npm test" — fully automated with test command
/git-bisect-ai --good v2.1.0 --bad HEAD — specify known good/bad points
/git-bisect-ai --perf "p99 latency" — performance regression bisect
How It Works
Binary search through commits: O(log n) — 1000 commits = ~10 steps.
Claude will:
- Ask for symptom + known good commit (or tag)
- Run
git bisect start - At each step: checkout commit → run test/check → mark good/bad
- Identify the culprit commit
- Explain what changed and why it likely caused the regression
- Suggest targeted fix or revert strategy
Workflow
Interactive Mode
/git-bisect-ai
Claude: What's the regression?
You: The /checkout page returns 500 after a database query
Claude: When did it last work?
You: It was fine in the v3.2.0 release
Claude will:
git bisect start
git bisect bad HEAD
git bisect good v3.2.0
→ [steps through 8 commits]
→ Found: commit abc1234
"feat: add discount coupon support"
→ Changed: src/checkout/service.ts line 142
Added raw SQL interpolation (SQL injection + syntax error in some locales)
Automated Mode (with test script)
git bisect start
git bisect bad HEAD
git bisect good v3.2.0
# Claude generates and runs:
git bisect run bash -c '
npm run build:quiet &&
curl -s -o /dev/null -w "%{http_code}" \
http://localhost:3000/api/checkout | grep -q 200
'
# Exits 0 = good, non-0 = bad
Performance Regression Mode
/git-bisect-ai --perf
Claude measures p95 latency at each bisect step:
Commit abc → p95: 95ms (good)
Commit def → p95: 850ms (bad)
Commit ghi → p95: 102ms (good)
→ Culprit: commit def
"refactor: extract UserService"
Introduced N+1 query in user.findByEmail()
Bisect Script Templates
HTTP status check
git bisect run bash -c 'npm start &>/dev/null & sleep 3 && \
STATUS=$(curl -s -o /dev/null -w "%{http_code}" http://localhost:3000/api/health) && \
kill %1 && [ "$STATUS" = "200" ]'
Unit test
git bisect run npm test -- --testPathPattern="checkout.test.ts" --silent
Build check
git bisect run npm run build 2>/dev/null
Performance threshold
git bisect run bash -c '
npm start &>/dev/null & sleep 3 &&
LATENCY=$(curl -s -w "%{time_total}" -o /dev/null http://localhost:3000/api/products) &&
kill %1 &&
echo "$LATENCY < 0.5" | bc -l | grep -q 1
'
After Finding Culprit
Claude will show:
BISECT RESULT
==============
Culprit commit: abc1234f
Author: Jane Doe <jane@example.com>
Date: 2026-06-10 14:32 UTC
Message: "feat: add discount coupon support"
CHANGED FILES
src/checkout/service.ts (+47, -12)
src/models/coupon.ts (+120, -0) ← NEW FILE
ROOT CAUSE (line 142 in service.ts)
const query = `SELECT * FROM orders WHERE code = '${couponCode}'`
← SQL injection + breaks on quotes in coupon codes (e.g., "MOTHER'S-DAY")
OPTIONS
1. Fix: Parameterize query → db.query('...WHERE code = $1', [couponCode])
2. Revert: git revert abc1234f (creates new commit, safe for main)
3. Cherry-pick fix onto v3.2.0 patch branch