engineering-handbook/pull-requests.md

# Pull Requests

## Scope

Each PR should represent a single logical change. If you find yourself writing "and" in the title, consider splitting it into separate PRs.

| Good scope | Too broad |
|---|---|
| Add receipt parser Lambda | Add receipt parser and refactor auth middleware |
| Fix timeout in payment processor | Fix timeout and update dependencies |
| Update Lambda runtime to Python 3.12 | Update runtime and add new endpoint |

## Title

- Keep it under 70 characters
- Use the Conventional Commit format, same as commit messages (`type(scope): description`)
- Describe the change, not the ticket

| Good | Bad |
|---|---|
| `feat: add retry logic for transient upstream failures` | `JIRA-123` |
| `fix: correct null check in auth handler` | `Bug fix` |
| `build: update Lambda runtime to Python 3.12` | `Updates` |

## Description

Use a structured format:

```markdown
## Summary
What changed and why — 1-3 sentences. Explain the motivation, not just the diff.

## Validation
How you verified it works — steps taken, commands run, screenshots if UI.

## Tests
What tests were added, updated, or run. If no automated tests, explain manual testing.

## Notes
Anything reviewers should know — migration steps, deploy order, follow-ups, breaking changes. Omit this section if empty.
```

The summary should explain **why** the change is needed, not just restate the diff. Reviewers can read the code; they need context.

## When to Open a PR

- Before deploying to production (see [deploy-then-merge](git-workflow.md) workflow)
- When the work is ready for review, not as a draft for parking incomplete work
- After verifying locally that the change works as expected

## Merging

- Squash merge for feature branches with messy interim commits
- Regular merge for branches with clean, meaningful commit history
- Delete the branch after merge