PR Description Writer

Write a pull request description that respects the reviewer's time: they should grasp the what and why in 30 seconds and know exactly what to scrutinize.

Workflow

- [ ] 1. Read the diff and commits on the branch
- [ ] 2. If a PR template exists, fill it; otherwise use the structure below
- [ ] 3. Write a precise title and a why-focused summary
- [ ] 4. List the meaningful changes; call out risk and how it was tested
- [ ] 5. Link issues; add screenshots for UI; flag follow-ups

Step 1 — Read the actual change

Base the description on the diff, not the branch name:

Changes vs base: !`git diff $(git merge-base HEAD origin/main 2>/dev/null || echo origin/main)...HEAD --stat`
Commits: !`git log $(git merge-base HEAD origin/main 2>/dev/null || echo origin/main)..HEAD --pretty=format:"%s"`

Respect an existing template if the repo has .github/PULL_REQUEST_TEMPLATE.md.

Step 2 — Title

Use the Conventional Commit form so it reads well in history and release tooling: type(scope): imperative summary, ≤ ~70 chars, no trailing period. Example: fix(auth): refresh expired tokens before retrying requests.

Step 3 — Description structure

## Summary
<1–3 sentences: what this PR does and WHY. Lead with the motivation/problem.>

## Changes
- <Meaningful change 1 (group by area; describe behavior, not every file)>
- <Meaningful change 2>

## Why
<Context a reviewer needs: the bug's root cause, the design decision and alternatives
considered, links to the issue or discussion.>

## Testing
- <How you verified it: tests added, manual steps, edge cases checked>
- <How a reviewer can reproduce/verify>

## Screenshots / Recordings
<Before/after for any UI change>

## Notes for reviewers
- <Where to focus; known limitations; follow-up work; anything intentionally out of scope>

Closes #<issue>

Drop sections that don't apply (e.g. no Screenshots for a backend-only change).

Writing rules

• Why over what. The diff already shows what changed; the description must explain why and the decisions behind it.
• Summarize, don't transcribe. Group changes by area and describe behavior; don't list every file — that's what the diff is for.
• Surface risk. Explicitly call out anything risky: migrations, data backfills, config or env changes, feature flags, breaking changes, performance-sensitive paths.
• Make it reviewable. Tell the reviewer where to look first and what to verify. If the PR is large, suggest a reading order or note it could be split.
• Link, don't repeat. Reference the issue/RFC instead of re-explaining it.

Example

Branch diff: adds retry-with-refresh to the API client; touches client.ts, auth.ts, plus tests.

Output:

fix(auth): refresh expired tokens before retrying failed requests

## Summary
API calls were failing with 401s right after a token expired, surfacing as random logout
errors. This refreshes the access token once and retries the request transparently.

## Changes
- Add a response interceptor that catches 401s, refreshes the token, and replays the request.
- Deduplicate concurrent refreshes so a burst of 401s triggers a single token refresh.
- Add unit tests for the single-flight refresh and the no-infinite-loop guard.

## Why
Root cause: the client treated every 401 as fatal. We chose interceptor-level handling over
per-call retry logic to keep call sites unchanged. A refresh lock prevents a thundering herd.

## Testing
- New tests: refresh-and-retry succeeds; second 401 after refresh does NOT loop.
- Manual: forced token expiry locally; confirmed seamless recovery, one /refresh call.

## Notes for reviewers
- Focus on the single-flight lock in `auth.ts` — concurrency is the tricky part.
- Out of scope: refresh-token rotation (tracked in #512).

Closes #498

Common edge cases

• Huge PR: recommend splitting; if not feasible, provide a guided reading order and call out the few files that carry the real logic.
• Pure refactor / no behavior change: say so explicitly and explain how you confirmed behavior is unchanged (e.g. tests untouched and passing).
• Dependency bumps: note what changed, why, and whether anything is breaking.
• Draft PR: state what's done, what's left, and what feedback you're seeking.