architecture-patterns

- Single responsibility boundaries - Interface contracts and type safety - Dependency injection patterns - Module cohesion and coupling analysis ### Data Flow - Request/response patterns - Event-driven architecture - State management strategies - Data transformation pipelines ### Integration Patterns - API design (REST, GraphQL, RPC) - Message queuing and async processing - Service boundaries and communication - Error propagation across boundaries ### Scalability - Horizontal vs vertical scaling considerations - Caching strategies - Database design and query optimization - Load balancing and distribution ## Decision Checkpoints Architectural decisions require user approval when: - Introducing new service boundaries - Changing data flow patterns - Adding new external dependencies - Modifying public API contracts ## When to Use - During PLAN workflow architecture phases - During BUILD when architectural choices arise - When reviewing system design in REVIEW workflow ## Agents Used - `planner` (architecture planning) - `component-builder` (architecture implementation) - `code-reviewer` (architecture review)