45ck inheritance-vs-composition-advisor
Purpose
Decide whether a relationship should be modeled through inheritance, composition, aggregation, or delegation.
Trigger this skill when
- A base class feels forced.
- Reuse is being modeled structurally rather than behaviorally.
- You need to choose between subclassing and containment/delegation.
Expected inputs
- class relationships
- reuse goal
- behavioral variance
- state ownership
- extensibility needs
Deliverables
- relationship decision
- rationale
- tradeoff summary
- alternative structure proposal
- recommended next step
Operating procedure
- Identify the object-oriented concern this skill is meant to assess.
- Separate facts from inferred design intent.
- Review the current structure against OOP fundamentals: responsibility, invariants, ownership, exposure, abstraction, and lifecycle where relevant.
- Surface concrete risks, tradeoffs, and improvement options.
- Prefer minimal structural change that materially improves clarity or safety.
- Hand off to the next most relevant skill if the issue is broader than this skill alone can resolve.
Quality gates
- Findings are tied to concrete code structure or stated design intent.
- Recommendations explain why, not just what.
- Tradeoffs are stated when multiple designs could work.
- Output avoids style nitpicks unless they affect abstraction or maintainability.
Handoff targets
- class-responsibility-checker
- overloading-overriding-reviewer
- object-lifecycle-reviewer
Output style
- Be explicit about uncertainty.
- Prefer short, evidence-based findings over long vague critique.
- Distinguish design defects from mere preference.
- End with recommended next actions.
Failure modes to avoid
- Do not invent framework constraints without evidence.
- Do not recommend sweeping refactors without naming the benefit.
- Do not confuse naming/style issues with true design problems unless they affect abstraction.
- Do not force inheritance, immutability, or statics as ideology.
Minimum output skeleton
## Summary
## Findings
## Risks
## Recommendations
## Tradeoffs
## Recommended next skill