chained-pr

Activation Contract

Load this skill when a planned PR may exceed 400 changed lines, SDD forecasts 400-line budget risk: High or Chained PRs recommended: Yes, or the user asks for chained/stacked PRs, review slices, or reviewer-load control.

Hard Rules

• Split PRs over 400 changed lines unless a maintainer explicitly accepts size:exception.
• The budget constrains how work is sliced, never the code itself. Never delete comments, blank lines, docs, or tests, and never compress or restyle code, to fit under the budget.
• Slicing is bounded: make one honest slicing pass. If no cohesive split brings every slice within budget, stop iterating, keep the best cohesive split, and report the final line count with a size:exception recommendation.
• 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 📍.
• In Feature Branch Chain, create a draft/no-merge tracker PR; child PR #1 targets the tracker branch, later children target the immediate parent branch.
• Treat polluted diffs as base bugs: retarget or rebase until only the current work unit appears.
• Do not mix chain strategies after the user chooses one.

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 maintainer for size:exception. |

| No cohesive split fits the budget after one slicing pass | Stop; deliver the best split, report the overage and why it cannot shrink further, and recommend size:exception. |

| SDD provides delivery_strategy | Follow it before apply/PR creation. |

Execution Steps

1. Estimate changed lines and identify independent work units.
2. Ask for a chain strategy when none is cached and the budget is exceeded.
3. Create branches/PRs using the chosen strategy only.
4. Add Chain Context to each PR without replacing the repo PR template.
5. Verify each PR independently: CI/tests/docs/manual checks, rollback scope, and clean diff.
6. Keep tracker PR draft/no-merge until all child PRs are reviewed and integrated.

Output Contract

Return the chosen strategy, PR order, current PR boundary, dependency diagram, review budget (additions + deletions), verification plan, and any size:exception rationale.

References

• [references/chaining-details.md](references/chaining-details.md) — strategy diagrams, PR body section, branch commands, and reviewer guidance.