Clean Code Principles

Apply principles as constraints, not dogma. Prefer measurable maintainability over theoretical purity.

Use This Skill When

• Refactoring complex modules with coupling and duplication.
• Reviewing architecture decisions or PR quality.
• Designing reusable TypeScript services/components.

Principles to Apply

SOLID

• SRP: one reason to change per unit.
• OCP: extend behavior without modifying stable core.
• LSP: subtype must preserve contract behavior.
• ISP: small consumer-focused interfaces.
• DIP: depend on abstractions, not concrete details.

Supporting Rules

• DRY: remove duplicated business logic.
• KISS: prefer simple control flow and explicit naming.
• YAGNI: avoid speculative abstractions.

Refactor Workflow

1. Detect smells:

• large functions/classes
• feature envy
• repeated condition branches
• temporal coupling

2. Write/extend tests around current behavior.
3. Extract boundaries:

• interfaces
• services
• adapters

4. Reduce responsibilities and dependencies.
5. Re-run tests and compare behavior.

Code Review Checklist

• Does this change reduce or increase coupling?
• Are contracts explicit and stable?
• Is duplication reduced meaningfully?
• Are dependencies inverted where needed?
• Is complexity lower than before?

Output Requirements for Agent

• Identify concrete smells with file-level evidence.
• Recommend smallest safe refactor sequence.
• State tradeoffs and migration risks.
• Provide test strategy for behavior preservation.

References

• Detailed examples and before/after refactors: references/guide.md