MCP-WTIT

# Architecture ## Overview This MCP server is designed based on Clean Architecture principles. By placing business logic at the center and minimizing external dependencies, we achieve a testable and maintainable codebase. ## Layer Structure ### 1. Domain Layer (`src/domain/`) - **Responsibility**: Implementation of business logic and business rules - **Dependencies**: None (completely independent) - **Key Components**: - `interfaces/`: Domain service interface definitions - `services/`: Business logic implementation (TimeService) ### 2. Application Layer (`src/application/`) - **Responsibility**: Use case implementation and application-specific business rules - **Dependencies**: Domain layer only - **Key Components**: - `interfaces/`: Use case interface definitions - `usecases/`: Use case implementations - GetCurrentTimeUseCase ### 3. Infrastructure Layer (`src/infrastructure/`) - **Responsibility**: Integration with external systems (MCP SDK) - **Dependencies**: Application layer, Domain layer - **Key Components**: - `mcp/`: MCP server implementation ### 4. Shared Layer (`src/shared/`) - **Responsibility**: Type definitions and utilities shared across all layers - **Key Components**: - `types/`: Common type definitions - `errors/`: Custom error classes ### 5. Dependency Injection (`src/di/`) - **Responsibility**: Object creation and dependency management - **Key Components**: - `container.ts`: DI container using singleton pattern ## Data Flow ``` MCP Client ↓ TimeServer (Infrastructure) ↓ UseCase (Application) ↓ TimeService (Domain) ``` ## Design Principles ### SOLID Principles 1. **Single Responsibility Principle**: Each class has a single responsibility 2. **Open-Closed Principle**: Open for extension, closed for modification 3. **Liskov Substitution Principle**: Abstraction through interfaces 4. **Interface Segregation Principle**: Minimal necessary interfaces 5. **Dependency Inversion Principle**: Higher layers don't depend on lower layers ### Testability - Each layer can be tested independently - Easy mock creation using interfaces - Utilization of pure functions ## Technology Stack - **Language**: TypeScript 5.6+ - **Module System**: ESModules - **Testing**: Vitest - **Linting**: ESLint 9 - **Build**: TypeScript Compiler - **Runtime**: Node.js 18+