git-diff-summariser

Git diff summariser

When to use

The user pastes or points at a git diff and wants a summary rather than reading it line-by-line.

Examples:

Get the diff content. Either the user pasted it, or they point at a file — use fs_read on a .diff / .patch file. If you have sandbox access and a git repo cloned in /workspace, the shell script below can regenerate the diff.

Run the bundled counter (optional quick-stats pass). This gives accurate line/file counts without the model having to count manually:

run_skill_script({
  name: "git-diff-summariser",
  path: "scripts/count.sh",
  stdin: <the diff content>
})

Returns stdout like:

files_changed: 7
insertions: 142
deletions: 38
binary_files: 1

Read the diff yourself. The stats tell you the shape; now actually read the diff to understand what changed. Group changes by file or by logical theme (not by commit).
Produce four sections.
- Summary — one paragraph: what was the goal of these changes?
- Changes — bullet list grouped by theme, each with the file(s) affected
- Risk — anything that could break? (migrations, auth, public API, env vars, cron schedules)
- Commit message — a single-line subject + optional body, conventional-commits style (feat(module): …, fix(module): …, refactor(module): …)
Offer next steps. offer_choices:
- "Write this as a PR description"
- "Generate a test plan for these changes"
- "Flag any missing tests"

For the commit subject line, imperative mood, ≤72 chars.
Risk section should be honest — if there's no risk, say "Low — isolated changes to X".
Don't restate what the stats already show; the reader has them.
Reference files by relative path — src/foo.ts not a/src/foo.ts.