chained-pr

name	chained-pr
description	Trigger: PRs over 400 lines, stacked PRs, review slices. Split oversized changes into chained PRs that protect review focus.
license	Apache-2.0
metadata	{"author":"gentleman-programming","version":"1.0"}

Activation Contract

Load this skill when a planned PR may exceed 400 changed lines or the user asks for chained/stacked PRs, review slices, or reviewer-load control.

Hard Rules

• Split PRs over 400 changed lines unless the maintainer explicitly accepts size:exception.
• Keep each PR reviewable in about ≤60 minutes.
• Use one deliverable work unit per PR; keep tests/docs with the unit they verify.
• State start, end, prior dependencies, follow-up work, and out-of-scope items in every chained PR.
• Every child PR must include a dependency diagram marking the current PR with 📍.
• Treat polluted diffs as base bugs: retarget or rebase until only the current work unit appears.

Decision Gates

Condition	Action
PR ≤400 changed lines and focused	Keep single PR.
PR >400, each slice can land independently	Use Stacked PRs to main.
PR >400, feature must integrate before main	Use Feature Branch Chain with tracker.
Generated/vendor/migration diff cannot split cleanly	Ask for size:exception.

Execution Steps

1. Estimate changed lines and identify independent work units.
2. Ask for a chain strategy when the budget is exceeded.
3. Create branches/PRs using the chosen strategy only.
4. Add Chain Context to each PR (link to previous and next).
5. Verify each PR independently: CI/tests/docs/manual checks.
6. Keep tracker PR draft/no-merge until all child PRs are integrated.

Output Contract

Return: chosen strategy, PR order, current PR boundary, dependency diagram, review budget (additions + deletions), verification plan.

Gotchas

• Forgetting 📍 on the current PR in the dependency diagram — reviewers lose track of where they are in the chain
• Not asking for size:exception when the change genuinely can't split — silence looks like it was forgotten
• Creating a tracker PR that gets accidentally merged before all child PRs land — keep it in draft until the chain is complete
• Retargeting child PRs without rebasing first — polluted diffs make review impossible

Commands

gh pr view <PR_NUMBER> --json additions,deletions,changedFiles
git log --oneline main..HEAD