MySQL MCP Server

MySQL MCP Server

A sophisticated Model Context Protocol (MCP) server that provides secure, multi-database MySQL access with configurable security levels, lazy loading, and hot reload capabilities.

🚀 Features

• 🗄️ Multi-Database Support: Configure and access multiple MySQL databases simultaneously
• 🔒 Configurable Security: Four security levels from read-only to full access
• ⚡ Lazy Loading: Connection pools created only when needed for optimal resource usage
• 🔄 Hot Reload: Database configuration updates without server restart
• 📊 Complete Schema Information: Full table definitions with indexes, foreign keys, and constraints
• 🛡️ Explicit Database Selection: Required database parameter prevents accidental operations
• 🎯 MCP Protocol Integration: Native VS Code integration with resource browsing

🔧 Installation

1. Clone and Install
   git clone <your-repository-url> cd mysql-mcp-server npm install
2. Configure Multi-Database SetupCopy the example configuration file and customize it:
   cp .env.example .env
   Edit .env with your database configurations:
   # Multi-Database Configuration (JSON Array) MYSQL_DATABASES='[ { "name": "primary_db", "host": "localhost", "user": "your_username", "password": "your_password", "database": "your_database" }, { "name": "analytics_db", "host": "analytics.example.com", "user": "analytics_user", "password": "analytics_password", "database": "analytics" } ]' # Security Configuration # Options: (default), extended, all, or custom comma-separated list # MYSQL_ALLOWED_COMMANDS=extended # Connection Pool Settings MYSQL_CONNECTION_LIMIT=4 MYSQL_WAIT_FOR_CONNECTIONS=true # Server Metadata MCP_SERVER_NAME=mysql-mcp-server MCP_SERVER_VERSION=1.0.0
3. Add to VS Code MCP ConfigurationAdd to your VS Code settings.json under MCP servers:
   { "mcp": { "mcpServers": { "mysql-mcp-server": { "command": "node", "args": ["C:/path/to/mysql-mcp-server/mcp-mysql-lite.js"], "env": {} } } } }

🔒 Security Levels

Configure MYSQL_ALLOWED_COMMANDS in your .env file:

Default (Recommended)

Allowed Commands: SELECT, SHOW, DESCRIBE, DESC, EXPLAIN, ANALYZE
Use Case: Safe read-only access for data analysis and exploration

Extended

Allowed Commands: All default commands plus CREATE TABLE, ALTER TABLE, DROP TABLE, INSERT, UPDATE, DELETE, TRUNCATE, etc.
Use Case: Development environments where schema and data modifications are needed

All (⚠️ Use with Extreme Caution)

Allowed Commands: No restrictions - all SQL commands permitted
Use Case: Trusted environments requiring full database administration capabilities

Custom

Allowed Commands: User-defined comma-separated list
Use Case: Specific operational requirements with tailored permissions

🛠️ Available Tools

All tools require explicit database selection for security.

query_database

Execute SQL queries with security validation and explicit database selection.

• Parameters:
  • sql (string, required) - The SQL query to execute
  • database (string, required) - Database name to target (security requirement)
• Security: Commands validated against current security level
• Returns: Query results with execution metadata

describe_table

Get complete table structure using SHOW CREATE TABLE for comprehensive schema information.

• Parameters:
  • table_name (string, required) - Name of the table to describe
  • database (string, required) - Database containing the table (security requirement)
• Returns: Full table definition including columns, indexes, foreign keys, and engine details

list_databases

Display all configured databases and their connection status.

• Parameters: None required
• Returns: Database configurations with connection pool status and default database indicator

📚 Available Resources

Tables from the default database are exposed as MCP resources with URIs like:

Browse table schemas directly through VS Code's resource explorer.

💡 Usage Examples

Basic Database Query

Database: primary_db

Multi-Database Operations

Database: analytics_db

Table Schema Exploration

Use describe_table tool:

• Table: users
• Database: primary_db

Returns complete table definition with foreign keys, indexes, and constraints.

Database Discovery

Use list_databases tool to see all configured databases and their connection status:

🔄 Hot Reload Feature

Update database configurations in .env file - they'll be automatically reloaded:

• ✅ Credential updates: New passwords/users applied immediately
• ✅ New databases: Added to available list (restart VS Code to update tool schemas)
• ✅ Configuration changes: Host/port updates applied on next connection
• 🔄 Existing connections: Remain active until naturally recycled

⚡ Lazy Loading

Connection pools are created only when needed:

• 📊 Resource efficient: No unnecessary database connections
• 🚀 Fast startup: Server starts immediately regardless of database availability
• 🔍 Status visibility: list_databases shows which pools are active
• 🛡️ Failure isolation: One database issue doesn't affect others

🏗️ Architecture

Key design principles:

• Multi-Database: Each database has independent configuration and connection pool
• Security: Command validation before execution, explicit database selection required
• Performance: Lazy loading + connection pooling for optimal resource usage
• Reliability: Hot reload + error isolation for production stability

🚀 Development

Running the Server

Testing Configuration

Environment Variables

• MYSQL_DATABASES: JSON array of database configurations
• MYSQL_ALLOWED_COMMANDS: Security level (default/extended/all/custom)
• MYSQL_CONNECTION_LIMIT: Max connections per pool (default: 4)
• MYSQL_WAIT_FOR_CONNECTIONS: Wait for available connections (default: true)

📄 License

MIT License - see LICENSE file for details.

Built with ❤️ for the Model Context Protocol ecosystem