Bisect Mode
Find the breaking commit. Bisect automates binary search through your Git history to pinpoint exactly when a regression was introduced.
Find the breaking commit.
Bisect mode automates the process of identifying which commit introduced a regression. Using binary search across your Git history, it tests each candidate and narrows down to the exact commit responsible — without you having to check each one manually.
What it does
Bisect mode runs an automated binary search through the commit history. It takes a known-good state and the current broken state, then systematically tests commits in between — halving the search space at each step — until the culprit commit is identified. Once found, it surfaces the commit details and optionally proposes a fix.
When to use it
- "This worked two weeks ago and now it doesn't"
- A regression was detected but the last change isn't the cause
- You need to pinpoint a breaking commit before reverting or fixing
- A CI test started failing somewhere in a long series of commits
- Performance degraded at some point and you need to find when
The more precisely you describe the regression, the more accurate the bisect. "The login button stopped working" is better than "something broke." Specific symptoms guide the test at each step.
How it works
- Describe the regression — explain what worked before and what's broken now. Include the current broken symptom.
- History scanned — the agent identifies the range of commits to search: from the last known-good state to the current broken HEAD.
- Binary search — commits are tested in bisect order. At each step, the agent checks out the commit and verifies whether the regression is present.
- Culprit identified — once the breaking commit is found, its details are surfaced: author, date, message, and the diff.
- Fix proposed — optionally, the agent proposes a fix or revert based on the breaking change.
Key features
- Automated binary search — no manual
git bisectcommands; the agent runs the full process - Systematic testing — each candidate commit is tested against the regression symptom
- Precise identification — narrows down to the single commit that introduced the problem
- Culprit details — the breaking commit is surfaced with full context (author, diff, message)
- Optional fix proposal — the agent can suggest a fix or revert once the commit is found
Tips
If you have a known good commit hash, provide it. This bounds the search and makes the bisect faster and more accurate.
Use Bisect before Bug mode when you suspect a regression but aren't sure where in the history it was introduced. Bisect finds the commit; Bug mode diagnoses the root cause.