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name: smith-design description: SOLID principles and architecture design patterns. Use when starting new features, refactoring code, conducting architecture reviews, or applying object-oriented design principles.

Design Principles

• Scope: SOLID principles for OOP/architecture design
• Load if: Starting new feature, refactoring, architecture review
• Prerequisites: @smith-principles/SKILL.md (fundamental principles: DRY, KISS, YAGNI, MECE)

SOLID Principles

• Single Responsibility: One reason to change per class/module
• Open/Closed: Open for extension, closed for modification
• Liskov Substitution: Subtypes must be substitutable for base types
• Interface Segregation: Many specific interfaces over one general
• Dependency Inversion: Depend on abstractions, not concretions

ACTION (Recency Zone)

When designing or reviewing architecture:

1. Apply Single Responsibility - each module has one reason to change
2. Design for extension without modification (Open/Closed)
3. Ensure subtypes are substitutable (Liskov)
4. Prefer small, focused interfaces (Interface Segregation)
5. Depend on abstractions, not implementations (Dependency Inversion)

Claude Code Plugin Integration

When pr-review-toolkit is available:

• type-design-analyzer agent: Rates type design on 4 dimensions (1-10 each)
  • Encapsulation
  • Invariant expression
  • Usefulness
  • Enforcement
• Trigger: "Review the [TypeName] type design" or use Task tool

• @smith-principles/SKILL.md - Fundamental principles (DRY, KISS, YAGNI)
• @smith-standards/SKILL.md - Universal code standards
• @smith-dev/SKILL.md - Development workflow
• @smith-analysis/SKILL.md - Problem decomposition before design