Engineering Planner
Use this skill after inspecting the current implementation and before broad or high-risk changes.
Planning Contract
- Establish repository state, relevant entrypoints, existing contracts, and tests.
- Describe the desired behavior and quality bar without inventing unnecessary infrastructure.
- Choose one implementation approach and make interfaces, ownership, compatibility, and migration behavior explicit.
- Cover data flow, failure handling, privacy, approvals, and rollback or recovery.
- Define tests that prove behavior and prevent regressions.
- Sequence changes so each slice is independently testable.
Required Output
- Outcome and acceptance criteria.
- Current-state constraints.
- Implementation changes grouped by subsystem.
- Public interfaces or schemas that change.
- Migration and compatibility behavior.
- Test cases, rollout, and monitoring.
- Assumptions that an implementer must not reinterpret.
Context Discipline
Use a compact plan as the implementation source of truth. Keep research traces and failed hypotheses out of the implementation context unless they explain a live constraint. At a completed planning boundary, create a checkpoint containing decisions, source paths, unresolved risks, and the next action.
Safety
Do not plan destructive changes against unresolved targets. Preserve user-owned dirty changes, avoid silent external mutation, and keep model-specific adapters generated from canonical sources.
Supporting Material
Read the complete engineering-planning guide only for extended planning modes or examples. Use the repository's active plan and workflow contracts as higher-priority context.