mcp-database-server: Cursor rule for Cursor

PROJECT OVERVIEW

You are an expert Node.js developer tasked with building a Model Context Protocol (MCP) server that provides multi-database query execution capabilities. This server should support SQLite, PostgreSQL, and MySQL databases with a focus on security, performance, and extensibility using modern Node.js and TypeScript. Note: This project is mcp-server, not a web app or another app.

CORE REQUIREMENTS

1. MCP Protocol Implementation

• Implement full MCP server specification compliance
• Use JSON-RPC for client-server communication
• Provide proper error handling and response formatting
• Support async/await patterns with modern ES modules

2. Database Support

• SQLite: File-based database support with better-sqlite3 or sqlite3
• PostgreSQL: Production database support with pg (node-postgres)
• MySQL: Enterprise database support with mysql2
• Implement connection pooling for each database type
• Provide unified interface across all database types

3. Security Requirements

• MANDATORY: Use parameterized queries only (prevent SQL injection)
• Implement credential encryption for database connections
• Add query validation and sanitization
• Include audit logging for all database operations
• Support rate limiting and timeout controls

4. Architecture Pattern

• Use dependency injection for database drivers
• Implement proper connection lifecycle management
• Follow SOLID principles and clean architecture
• Use Zod for data validation and schema management
• Use TypeScript for type safety

PROJECT STRUCTURE

mcp-database-server/ ├── src/ │ ├── index.ts │ ├── server/ │ │ ├── index.ts │ │ ├── mcp-server.ts # Main MCP server implementation │ │ ├── handlers.ts # Request handlers │ │ └── tools/ # MCP tools implementation │ │ ├── index.ts │ │ ├── execute-query.ts │ │ ├── list-databases.ts │ │ ├── describe-table.ts │ │ └── list-tables.ts │ ├── database/ │ │ ├── index.ts │ │ ├── base.ts # Abstract base database interface │ │ ├── factory.ts # Database driver factory │ │ ├── pool.ts # Connection pooling │ │ └── drivers/ │ │ ├── index.ts │ │ ├── sqlite-driver.ts │ │ ├── postgresql-driver.ts │ │ └── mysql-driver.ts │ ├── config/ │ │ ├── index.ts │ │ ├── settings.ts # Configuration schemas │ │ └── database-config.ts # Database configurations │ ├── security/ │ │ ├── index.ts │ │ ├── encryption.ts # Credential encryption │ │ ├── validators.ts # Query validation │ │ └── audit.ts # Audit logging │ ├── utils/ │ │ ├── index.ts │ │ ├── logger.ts # Structured logging │ │ ├── exceptions.ts # Custom exceptions │ │ └── helpers.ts # Utility functions │ └── types/ │ ├── index.ts │ ├── database.ts │ ├── mcp.ts │ └── config.ts ├── tests/ │ ├── unit/ │ ├── integration/ │ └── fixtures/ ├── examples/ │ ├── basic-usage.js │ ├── configuration-examples/ │ └── client-examples/ ├── docs/ ├── package.json ├── package-lock.json ├── tsconfig.json ├── .env.example ├── .gitignore ├── README.md ├── jest.config.js └── LICENSE