Database MCP Server

⚠️ WARNING: This software is designed for use with testing and development databases only. It makes no assurances that it won't break your database or cause data loss. DO NOT use this software against production databases. Always use dedicated test/development database instances when working with AI assistants.

A Model Context Protocol (MCP) server that provides secure database connectivity for MySQL and PostgreSQL databases. Enable AI assistants in Claude Code, Cursor, and other agentic editors to query, analyze, and interact with your databases safely.

Features

• Multi-Database Support: Connect to MySQL and PostgreSQL databases
• Secure Access Control: Restrict access to specific databases and control connection limits
• Rich Schema Inspection: Get detailed table schemas, indexes, and metadata
• Query Execution: Run SELECT, INSERT, UPDATE, and DELETE operations
• Query Planning: View execution plans for performance optimization
• Paginated Data Access: Efficiently browse large datasets with pagination

Installation

go install github.com/jhoffmann/go-database-mcp@latest

Configuration

Configure the database connection using a connection string.

Create a .env file in your project directory:

PostgreSQL Examples

# Basic connection
DB_CONNECTION_STRING=postgresql://myuser:mypassword@localhost:5432/myapp

# With SSL requirements
DB_CONNECTION_STRING=postgresql://myuser:mypassword@localhost:5432/myapp?sslmode=require

# Optional: Allow access to additional databases
# DB_ALLOWED_NAMES=testdb,devdb,staging

MySQL Examples

# Basic connection
DB_CONNECTION_STRING=mysql://myuser:mypassword@localhost:3306/myapp

# Remote database with SSL
DB_CONNECTION_STRING=mysql://myuser:mypassword@db.example.com:3306/myapp?sslmode=require

# Optional: Allow access to additional databases
# DB_ALLOWED_NAMES=testdb,devdb,staging

Environment Variables

Variable	Description	Required	Default	Notes
DB_CONNECTION_STRING	Full database connection URL (postgresql:// or mysql://)	Yes	-	Primary configuration method
DB_SSL_MODE	SSL/TLS mode (none, prefer, require)	No	prefer	Can be set in connection string or separately
DB_MAX_CONNS	Maximum open connections	No	10	Connection pool setting
DB_MAX_IDLE_CONNS	Maximum idle connections	No	5	Connection pool setting
DB_ALLOWED_NAMES	Comma-separated list of additional allowed databases	No	-	Security setting

Integration with Agentic Editors

OpenCode (https://opencode.ai)

Add the MCP server to your OpenCode configuration:

1. Create or edit ~/.config/opencode/opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "database-mcp": {
      "type": "local",
      "command": ["go-database-mcp"],
      "enabled": true,
      "environment": {
        "DB_CONNECTION_STRING": "postgresql://myuser:mypassword@localhost:5432/myapp"
      }
    }
  }
}

2. Restart OpenCode to load the MCP server

Claude Code (https://www.anthropic.com/claude-code)

Add the MCP server to your Claude Code configuration:

1. Create or edit ~/.config/claude-code/mcp_servers.json:

{
  "mcpServers": {
    "database": {
      "command": "go-database-mcp",
      "args": [],
      "env": {
        "DB_CONNECTION_STRING": "postgresql://myuser:mypassword@localhost:5432/myapp"
      }
    }
  }
}

2. Restart Claude Code to load the MCP server

Cursor IDE (https://cursor.com)

Configure the MCP server in your Cursor settings:

1. Open Cursor Settings → Extensions → MCP
2. Add a new MCP server configuration:

{
  "name": "Database Server",
  "command": "go-database-mcp",
  "args": [],
  "env": {
    "DB_CONNECTION_STRING": "mysql://app_user:secure_password@localhost:3306/ecommerce"
  }
}

Generic MCP Client Integration

For other MCP-compatible tools, configure the server with:

• Command: go-database-mcp (assuming it's in your PATH after go install)
• Transport: stdio
• Environment: Set DB_CONNECTION_STRING with your database connection URL

Available MCP Tools

Once connected, the following tools become available to your AI assistant:

• database_connection_info - Get current database connection details
• database_list_databases - List all available databases
• database_list_tables - List tables in the current database
• database_describe_table - Get detailed schema for a specific table
• database_get_table_data - Retrieve paginated table data
• database_query - Execute SQL queries with optional parameters
• database_explain_query - Get query execution plans

Usage Examples

Ask your AI assistant:

Schema Exploration:

• "What tables are in my database?"
• "Describe the structure of the users table"
• "Show me the indexes on the orders table"

Data Analysis:

• "What are the top 10 customers by total order value?"
• "Show me user registration trends over the last 6 months"
• "Find all orders placed in the last week"

Query Optimization:

• "Explain the execution plan for this slow query"
• "How can I optimize this JOIN operation?"
• "What indexes should I add to improve performance?"

Security Considerations

• Database Access Control: Use DB_ALLOWED_NAMES to restrict which databases can be accessed
• User Permissions: Create database users with minimal required permissions
• Connection Limits: Set appropriate DB_MAX_CONNS to prevent connection exhaustion
• SSL/TLS: Always use encrypted connections when available (DB_SSL_MODE=require). Available modes: none (no encryption, default), prefer (attempt SSL, fallback to unencrypted), require (mandatory SSL)
• Environment Variables: Store sensitive credentials in environment variables, not in code