pr-writer

Write a standalone description structured around What/Why, Changes, Testing, Observability, and Risk & rollback. Explicitly enumerate every contract edge crossed (inbound routes, outbound calls, config keys, events, migrations) and flag breaking changes in a bold block at the top.

Defect detection peaks at 200-400 changed lines reviewed in a 60-90 minute session, per the SmartBear/Cisco study. Under 100 production lines is ideal, 100-300 is good, and anything over 500 lines or roughly 10 files should be split.

Apply the rule that if you cannot describe the PR without the word 'and', it is two PRs. Land cross-cutting refactors as separate PRs first, then stack dependent changes as a chain of small PRs rather than one bundled mega-PR.

A Conventional-Commit title is one imperative line in the form type(scope): summary, such as feat(api): add pagination to orders. It names the problem rather than the fix, and breaking changes are marked with an exclamation mark before the colon.

Migrations should follow expand/contract: additive nullable columns and new tables ship in an expand step, never in the same PR as the code depending on the new shape. Dropping old structures happens in a later deploy, and each migration needs a tested reverse.

Defect detection drops sharply beyond roughly 400 lines or 90 minutes of review, so oversized PRs get rubber-stamped instead of reviewed. File spread matters as much as raw lines, since 200 lines across 50 files exceeds effective review capacity.