# GitScope

GitScope is a CLI tool that turns git diffs into structured, machine-readable summaries of **what changed semantically** — not what lines changed, but what functions, classes, and APIs were added, removed, modified, or moved. A 500-line diff becomes a ~200-token structured summary with signatures, breaking changes, and review focus areas.

## Who it's for

**AI agents doing code review.** GitScope gives reviewer agents a structural map of a PR before they read the diff — a pre-pass that shifts attention from line-by-line scanning to design-level analysis.

## Why it exists

In a controlled A/B test, a reviewer agent with GitScope's structured output found **37% more issues** than with the raw diff alone — and the unique findings were disproportionately design-level bugs, not surface-level style issues. ([Full results](validation.md))

## Key properties

- **~200-300 tokens of output**, not thousands. Context conservation matters.
- **Structured JSON** with function signatures, breaking change flags, and tiered summaries
- **Sub-500ms** for any diff under 1000 lines
- **CLI-first.** `git diff | gitscope summarize` — works with every agent platform via exec
- **Accuracy over comprehensiveness.** Wrong summaries are worse than no summaries.

## Quick start

```bash
uvx gitscope summarize HEAD~1..HEAD
```

→ [Installation & usage](quickstart.md)
