pr-writer

--- name: pr-writer description: Create or refresh reviewer-facing PR titles and descriptions. Use when opening a PR, updating its title or body, or preparing branch changes for review. ---

# PR Writer

Write the PR body as a cover note for reviewers, not a changelog, template, validation log, or file-by-file summary.

## Inspect the Change

Requires authenticated `gh`. Inspect the current branch, working tree, PR, base branch, commits, and full diff:

```bash git branch --show-current git status --porcelain gh pr view --json number,title,body,url,baseRefName,headRefName gh repo view --json defaultBranchRef ```

If `gh pr view` reports that no PR exists, continue with first-time PR creation. For an existing PR, use its `baseRefName`; otherwise use the repository default branch. Set `BASE`, then inspect:

```bash git log "$BASE"..HEAD --oneline git diff "$BASE"...HEAD ```

If on `main` or `master`, create a feature branch first. Ensure intended changes are committed and review the whole branch diff, not only the latest commit or existing PR text.

## Core Rules

- Describe concrete changed behavior, affected surfaces, and reviewer impact before implementation detail. - Explain motivation, risk, tradeoffs, migration, or review focus only when useful. - Use the smallest structure that makes the change easier to review. - Replace internal prompt or process terminology with specific behavior. - When refreshing a PR, rewrite around the current full diff without narrating review history.

## Titles

Use `<type>(<scope>): <subject>` or `<type>: <subject>`.

Allowed types: `feat`, `fix`, `ref`, `perf`, `docs`, `test`, `build`, `ci`, `chore`, `style`, `meta`, `license`, and `revert`.

- Describe the dominant full-branch change with the narrowest accurate type and scope. - Use `!` only when the change breaks an external contract, and explain the affected surface in the body. - Avoid vague subjects such as `update`, `cleanup`, `misc`, `fix stuff`, or `address feedback`. Do not add a trailing period. - Keep an existing title only when it still describes the whole diff.

## Body Shape

Choose the minimum useful shape:

| Change | Include | |--------|---------| | Small or obvious | One concise paragraph without headings. | | Feature, bug fix, or refactor | Changed behavior and effect; add root cause, unchanged behavior, or non-obvious approach when relevant. | | Contract or breaking change | Affected API, schema, payload, config, permission, storage, or CLI surface; include compatibility and migration guidance. | | Operational, visual, or workflow change | User/operator effect, measured impact, failure modes, or flow when useful. | | Broad, generated, or cross-cutting change | Organizing principle, why the breadth is necessary, and where review should start. |

Default:

```markdown <What changed and what effect it has.>

<Why the approach, risk, migration, or review focus matters, if not obvious.> ```

For review-feedback updates, describe the resulting PR as a whole rather than the sequence of revisions.

## Reviewer Aids

Use an aid only when it reduces reviewer reconstruction work:

- A compact before/after or interface example for changed contracts. - A small Mermaid diagram for async flows or state transitions. - A screenshot or recording note when visual evidence exists. - A rollout, compatibility, risk, or review-order note when reviewers or adopters need it.

Introduce an artifact with one sentence explaining what reviewers should notice. Omit it when prose is clearer.

## Boundaries

- Do not add default `Summary`, `Changes`, or `Test Plan` sections. - Omit routine validation unless it changes risk assessment or explains meaningful regression coverage. For docs, skills, copy, or config changes, omit it by default. - Do not paste commands, CI logs, validation dumps, commit logs, placeholders, or exhaustive file lists. - Never include customer or organization names, user emails, support ticket contents, secrets, or PII. - Use issue references only when verified from user input, branch names, commits, PR discussion, or tracker output. `Fixes <issue>` closes; `Refs <issue>` only links.

## Create or Update

Create new PRs as drafts. Write the body to a temporary Markdown file, then run:

```bash gh pr create --draft --title '<title>' --body-file /tmp/pr-body.md ```

Update existing PRs with `gh api`:

```bash gh api -X PATCH repos/{owner}/{repo}/pulls/PR_NUMBER \ -f title='<title>' \ -F body=@/tmp/pr-body.md ```

Refresh the title and body when follow-up commits materially change scope, approach, breaking behavior, risk, migration, or review expectations. Skip typo-only, formatting-only, and rename-only follow-ups.

## Examples

Small change:

```markdown The AI Customizations section now starts collapsed so it does not consume sidebar space before users need it. Expanding it preserves the existing saved preference behavior. ```

Breaking contract:

````markdown Run logs now emit chunk-level records instead of one skill-level record. Consumers that read top-level `findings` must iterate over `chunk.findings` for each record.

Before:

```json {"skill": "security-review", "findings": [...]} ```

After:

```json {"schemaVersion": 1, "chunk": {"index": 1, "findings": [...]}} ``` ````