/pr-summarizer

name: pr-summarizer
description: Use when opening a PR — produces a clean PR description (what / why / how to verify / risks) from a branch diff against base.
version: 0.1.0
status: experimental
risk: low
tags: [engineering, read-only, writes-files]

PR Summarizer

When to use

• Just before opening a PR
• After force-pushing a substantive update to an existing PR (refresh description)

When NOT to use

• Drafts the user is still iterating on (the summary will go stale immediately)
• Massive diffs (> 1000 lines) — ask the user to scope first

Inputs

| Name | Type | Required | Notes | |---|---|---|---| | `base` | string | no | default `origin/main` | | `branch` | string | no | default current `HEAD` |

Outputs

A markdown PR body with sections: **Summary**, **Why**, **How tested**, **Risks**, **Linked**.

Workflow

1. `git diff <base>...HEAD --stat` and `git log <base>..HEAD --oneline` to see scope 2. `git diff <base>...HEAD` for content 3. Group changes by area (one bullet per logical concern, not per file) 4. Pull "why" from commit messages + linked tickets if mentioned 5. Identify test artifacts touched; surface as **How tested** (or flag if none) 6. Risks: any High-risk paths touched? auth, billing, migrations? mention. 7. Linked: parse `Fixes #` / `Refs #` from commits

References

• [`references/pr-template.md`](references/pr-template.md)

Success criteria

• Description ≤ 25 lines
• Every "why" claim is supported by a commit message or visible in the diff
• Risks section honest about unknowns ("untested in production data shape")

Failure modes

• No commit messages worth quoting → "Why" sourced from diff only; flag this
• Diff touches secrets / `.env*` → STOP and surface; PR shouldn't include them