pull-request-automation

Pull Request Automation Skill

Step 1 — Audit Current PR Workflow

Check what already exists:

• Is there a .github/pull_request_template.md?
• Is there a .github/CODEOWNERS file?
• Are there existing labelling or size-check actions?
• Are branch protection rules configured for main?

Step 2 — PR Description Template

Create .github/pull_request_template.md:

## Summary

<!-- What does this PR do? Why? -->

## Changes

<!-- Bullet list of key changes -->

## Test Plan

- [ ] Unit tests added / updated
- [ ] Manual testing performed: <describe steps>
- [ ] Breaking changes documented

## Related Issues

Closes #

Keep the template short — the goal is consistency, not bureaucracy.

Step 3 — Auto-Labelling

Use actions/labeler to apply labels automatically based on changed file paths:

# .github/labeler.yml
frontend:
  - changed-files:
    - any-glob-to-any-file: "src/features/**"
backend:
  - changed-files:
    - any-glob-to-any-file: "internal/**"
docs:
  - changed-files:
    - any-glob-to-any-file: "docs/**"
infrastructure:
  - changed-files:
    - any-glob-to-any-file: "deployments/**"

# .github/workflows/labeler.yml
name: Label PR
on: [pull_request_target]
jobs:
  label:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/labeler@v5
        with:
          repo-token: ${{ secrets.GITHUB_TOKEN }}

Step 4 — CODEOWNERS

Define ownership in .github/CODEOWNERS. GitHub requests reviews from owners automatically when their files are touched:

# Global fallback
*                  @org/platform-team

# Frontend
/src/features/     @org/frontend-team

# Infrastructure
/deployments/      @org/infra-team
/build/            @org/infra-team

# Database migrations
/internal/infrastructure/migrations/  @org/dba-team

Step 5 — PR Size Check

Flag PRs that are too large to review effectively. Add a size-check action:

# .github/workflows/pr-size.yml
name: PR Size Check
on: [pull_request]
jobs:
  size:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with: { fetch-depth: 0 }
      - name: Check PR size
        run: |
          LINES=$(git diff --stat origin/${{ github.base_ref }}...HEAD | tail -1 | grep -oE '[0-9]+ insertions' | grep -oE '[0-9]+' || echo 0)
          if [ "$LINES" -gt 500 ]; then
            echo "::warning::PR adds $LINES lines. Consider splitting into smaller PRs."
          fi