GitHub PR Auto-Summarizer

What It Does

Paste a raw GitHub pull request diff and the tool returns a structured, reviewer-ready summary in under five seconds. It extracts:

• A one-sentence TL;DR
• Files changed and their purpose
• Risk areas and suggested test cases
• Reviewer focus checklist

The output format is Markdown, suitable for pasting directly into a PR comment or a Slack message.

Usage

Copy the diff output from GitHub (or git diff main...feature-branch) and paste it after the instruction below.

You are a senior software engineer performing a code review.
Given the following pull request diff, produce:

1. **TL;DR** (1 sentence)
2. **Changes summary** — bullet list, grouped by file or concern
3. **Risk areas** — anything that could break in production
4. **Suggested tests** — what the reviewer should manually verify
5. **Reviewer checklist** — 3–5 actionable items

Format your response in clean Markdown.

---DIFF---
[paste diff here]

Integration with GitHub Actions

# .github/workflows/pr-summary.yml
name: PR Summary
on:
  pull_request:
    types: [opened, synchronize]

jobs:
  summarize:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Generate diff
        run: git diff origin/main...HEAD > /tmp/pr.diff

      - name: Post summary
        env:
          OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          python scripts/summarize_pr.py /tmp/pr.diff