MCP Server for MySQL based on NodeJS

A Model Context Protocol server that provides read-only access to MySQL databases. This server enables LLMs to inspect database schemas and execute read-only queries.

Installation

Using Smithery

The easiest way to install and configure this MCP server is through Smithery:

During configuration, you'll be prompted to enter your MySQL connection details. Smithery will automatically:

• Set up the correct environment variables

• Configure your LLM application to use the MCP server

• Test the connection to your MySQL database

• Provide helpful troubleshooting if needed

Using MCP Get

You can also install this package using MCP Get:

MCP Get provides a centralized registry of MCP servers and simplifies the installation process.

Using NPM/PNPM

For manual installation:

After manual installation, you'll need to configure your LLM application to use the MCP server (see Configuration section below).

Components

Tools

• mysql_query

  • Execute read-only SQL queries against the connected database

  • Input: sql (string): The SQL query to execute

  • All queries are executed within a READ ONLY transaction

  • Supports prepared statements for secure parameter handling

  • Configurable query timeouts and result pagination

  • Built-in query execution statistics

Resources

The server provides comprehensive database information:

• Table Schemas

  • JSON schema information for each table

  • Column names and data types

  • Index information and constraints

  • Foreign key relationships

  • Table statistics and metrics

  • Automatically discovered from database metadata

Security Features

• SQL injection prevention through prepared statements

• Query whitelisting/blacklisting capabilities

• Rate limiting for query execution

• Query complexity analysis

• Configurable connection encryption

• Read-only transaction enforcement

Performance Optimizations

• Optimized connection pooling

• Query result caching

• Large result set streaming

• Query execution plan analysis

• Configurable query timeouts

Monitoring and Debugging

• Comprehensive query logging

• Performance metrics collection

• Error tracking and reporting

• Health check endpoints

• Query execution statistics

Configuration

Automatic Configuration with Smithery

If you installed using Smithery, your configuration is already set up. You can view or modify it with:

Manual Configuration for Claude Desktop App

To manually configure the MCP server for Claude Desktop App, add the following to your claude_desktop_config.json file (typically located in your user directory):

Replace db_name with your database name or leave it blank to access all databases.

Advanced Configuration Options

For more control over the MCP server's behavior, you can use these advanced configuration options:

Environment Variables

Basic Connection

• MYSQL_HOST: MySQL server host (default: "127.0.0.1")

• MYSQL_PORT: MySQL server port (default: "3306")

• MYSQL_USER: MySQL username (default: "root")

• MYSQL_PASS: MySQL password

• MYSQL_DB: Target database name

Performance Configuration

• MYSQL_POOL_SIZE: Connection pool size (default: "10")

• MYSQL_QUERY_TIMEOUT: Query timeout in milliseconds (default: "30000")

• MYSQL_CACHE_TTL: Cache time-to-live in milliseconds (default: "60000")

Security Configuration

• MYSQL_RATE_LIMIT: Maximum queries per minute (default: "100")

• MYSQL_MAX_QUERY_COMPLEXITY: Maximum query complexity score (default: "1000")

• MYSQL_SSL: Enable SSL/TLS encryption (default: "false")

Monitoring Configuration

• MYSQL_ENABLE_LOGGING: Enable query logging (default: "false")

• MYSQL_LOG_LEVEL: Logging level (default: "info")

• MYSQL_METRICS_ENABLED: Enable performance metrics (default: "false")

Testing

Database Setup

Before running tests, you need to set up the test database and seed it with test data:

1. Create Test Database and User

   -- Connect as root and create test database CREATE DATABASE IF NOT EXISTS mcp_test; -- Create test user with appropriate permissions CREATE USER IF NOT EXISTS 'mcp_test'@'localhost' IDENTIFIED BY 'mcp_test_password'; GRANT ALL PRIVILEGES ON mcp_test.* TO 'mcp_test'@'localhost'; FLUSH PRIVILEGES;

2. Run Database Setup Script

   # Run the database setup script pnpm run setup:test:db

   This will create the necessary tables and seed data. The script is located in scripts/setup-test-db.ts

3. Configure Test Environment Create a .env.test file in the project root:

   MYSQL_HOST=127.0.0.1 MYSQL_PORT=3306 MYSQL_USER=mcp_test MYSQL_PASS=mcp_test_password MYSQL_DB=mcp_test

4. Update package.json Scripts Add these scripts to your package.json:

   { "scripts": { "setup:test:db": "ts-node scripts/setup-test-db.ts", "pretest": "pnpm run setup:test:db", "test": "vitest run", "test:watch": "vitest", "test:coverage": "vitest run --coverage" } }

Running Tests

The project includes a comprehensive test suite to ensure functionality and reliability:

Troubleshooting

Using Smithery for Troubleshooting

If you installed with Smithery, you can use its built-in diagnostics:

Using MCP Get for Troubleshooting

If you installed with MCP Get:

Common Issues

1. Connection Issues

   • Verify MySQL server is running and accessible

   • Check credentials and permissions

   • Ensure SSL/TLS configuration is correct if enabled

   • Try connecting with a MySQL client to confirm access

2. Performance Issues

   • Adjust connection pool size

   • Configure query timeout values

   • Enable query caching if needed

   • Check query complexity settings

   • Monitor server resource usage

3. Security Restrictions

   • Review rate limiting configuration

   • Check query whitelist/blacklist settings

   • Verify SSL/TLS settings

   • Ensure the user has appropriate MySQL permissions

4. Path Resolution If you encounter an error "Could not connect to MCP server mcp-server-mysql", explicitly set the path of all required binaries:

5. Authentication Issues

   • For MySQL 8.0+, ensure the server supports the caching_sha2_password authentication plugin

   • Check if your MySQL user is configured with the correct authentication method

   • Try creating a user with legacy authentication if needed:

     CREATE USER 'user'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';

Contributing

Contributions are welcome! Please feel free to submit a Pull Request to https://github.com/benborla/mcp-server-mysql

Development Setup

1. Clone the repository

2. Install dependencies: pnpm install

3. Build the project: pnpm run build

4. Run tests: pnpm test

Project Roadmap

We're actively working on enhancing this MCP server. Check our CHANGELOG.md for details on planned features, including:

• Enhanced query capabilities with prepared statements

• Advanced security features

• Performance optimizations

• Comprehensive monitoring

• Expanded schema information

If you'd like to contribute to any of these areas, please check the issues on GitHub or open a new one to discuss your ideas.

Submitting Changes

1. Fork the repository

2. Create a feature branch: git checkout -b feature/your-feature-name

3. Commit your changes: git commit -am 'Add some feature'

4. Push to the branch: git push origin feature/your-feature-name

5. Submit a pull request

License

This MCP server is licensed under the MIT License. See the LICENSE file for details.