Write Pull Requests

Write Pull Requests

The description is the cheapest review tool the author controls: it decides whether the reviewer follows the change or reverse-engineers it. Two fixed shapes, filled from the diff and from output that actually scrolled by — never from memory of what you meant to build.

1. Audit — what does the branch ship, and does a PR exist?

git log main..HEAD --oneline          # substitute the repo's default branch
git diff main --stat                  # or: git show <sha>, for a PR shipping one existing commit
ls .github/PULL_REQUEST_TEMPLATE.md .github/pull_request_template.md \
   .github/PULL_REQUEST_TEMPLATE/ 2>/dev/null
gh pr view --json number,title,body 2>/dev/null

Change nothing yet. Three findings decide the rest:

• The diff is the source of truth. Describe what the branch ships — including the commit you forgot — not what you remember working on.
• A repo template wins. If .github/ defines a PR template, fill its sections in its order, and carry this skill's discipline into whatever slot asks for testing or verification. The shapes below apply only when the repo has none.
• An existing PR means update, not create. Step 5 edits it in place; never open a duplicate. If the body already matches what the branch now ships, exit — nothing to do.

2. Decide the shape

One question: does the branch restore intended behavior (bug fix) or change or extend it (feature)? Mixed branches lead with the dominant shape and carry the remainder under Notes. Edge cases (refactors, mixed branches): ./pr-patterns.md.

3. Fill the sections — exactly these, in this order

Bug fix:

1. Problem — the user-visible symptom, in plain words: what broke, who hit it.
2. Root cause — the mechanism actually found, not the first suspicion.
3. Fix — what changed, and why this way.
4. Tests — coverage added or extended; name the test that now catches the bug.
5. Verification — the commands run and their observed output. Evidence, never claims (./pr-patterns.md).
6. Notes — tradeoffs, follow-ups, review hints.

Feature:

1. Summary — two or three sentences a CTO reads first: what ships, why it matters.
2. Problem — the need, in plain words: what couldn't be done before.
3. Solution — the approach chosen; the rejected alternative in one line when the diff or commits record one — "Rejected: none recorded" is honest too.
4. Implementation — the shape of the change in the code: key files, seams touched.
5. Tests — coverage added or extended.
6. Verification — commands run and observed output.
7. Notes — tradeoffs, follow-ups, review hints.

Both shapes close with the merge checklist, posted unticked:

## Before merge
- [ ] Manual review
- [ ] Smoke tested
- [ ] Pipeline green

A box is ticked by whoever verified it — the reviewer for the manual read, the author or CI for the rest. A pre-ticked box with nothing behind it is decoration, not evidence.

No invented headings, no omissions: content that fits no section goes under Notes or stays out. For Verification, run the commands now and paste the lines that prove the point; anything not run is declared — "Not run: needs staging" — an honest gap beats a fabricated pass. Write the assembled body to /tmp/pr-body.md; step 5 posts that file.

4. Self-check against the audience contract

Read the draft as the three readers of ../_shared/audience.md:

• Junior — can they follow Problem → Fix (or Solution) without tribal knowledge? Every internal codename expanded on first use?
• Senior — does every claim have its evidence under Tests or Verification? A bare claim gets its proof moved in, or gets softened to what the evidence supports.
• CTO — do the headings and first lines alone carry outcome and risk?

Plain prose throughout. A sentence that reads like a release announcement gets rewritten as a fact.

5. Create or update

Show the title and body for approval first — pushing and opening a PR publish the draft.

git push -u origin HEAD               # if not yet pushed
gh pr create --title "<subject>" --body-file /tmp/pr-body.md
# or, when step 1 found an existing PR:
gh pr edit <number> --body-file /tmp/pr-body.md

The title carries the branch's dominant commit subject; a subject past ~72 characters is compressed — keep the type(scope): and the one concern (../write-commit-messages/SKILL.md). Editing the existing body in place is this skill's idempotency: a re-run regenerates the description from the current diff and lands on the same PR.

6. Verify

gh pr view

Expected: one PR for the branch; six (bug fix) or seven (feature) sections in the fixed order, closed by the Before-merge checklist — or the repo template's own; every Verification entry is a command plus its observed output, not an adjective.

References

• ./pr-patterns.md — why evidence beats assertion, Problem vs Summary, the shape decision, a filled example, when to deviate.
• ../_shared/audience.md — the junior-to-CTO contract step 4 checks against.
• ../write-commit-messages/SKILL.md — the commit subjects the title and Summary draw from.