MCP Database Tools

A Model Context Protocol (MCP) server that provides secure database access through MCP Server and other MCP-compatible clients.

🚀 Features

• YAML Configuration: Load database configurations from ~/.mcp-dbtools/config.yml
• Environment Variable Support: Use ${VAR_NAME} syntax for secure credential management
• Multiple Server Support: Configure and switch between different database connections
• SQL Execution: Execute SQL queries safely through the MCP protocol
• Fallback Support: Automatic fallback to environment variables if YAML config fails
• Comment-Safe Parsing: Environment variables in YAML comments are ignored

📋 Prerequisites

• Rust 1.70 or later
• A supported SQL database
• MCP Server (for MCP integration)

🛠️ Installation

1. Clone the repository:

   git clone <repository-url>
   cd mcp-dbtools
   

2. Build the project:

   cargo build --release
   

3. Create configuration directory:

   mkdir -p ~/.mcp-dbtools
   

⚙️ Configuration

YAML Configuration File

Create ~/.mcp-dbtools/config.yml:

# Configuration for MCP DB Tools
# Use ${VAR_NAME} to load sensitive values from environment variables.

servers:
  # Local development database
  test_db:
    adapter: "postgres"
    enabled: true
    host: "localhost"
    port: 5432
    username: "postgres"
    password: "postgres"  # WARNING: Use env vars for production
    dbname: "pocket_db"
    read_only: false
    
  # Production database
  prod_db:
    adapter: "mysql"
    enabled: true
    host: "prod.example.com"
    port: 3306
    username: "produser"
    password: "${PROD_DB_PASSWORD}"
    dbname: "production_db"
    read_only: true

Environment Variables

Set required environment variables:

export PROD_DB_PASSWORD="your-secure-password"

🏃‍♂️ Usage

Command Line

# Run with specific server configuration
cargo run --bin mcp-dbtools test_db

# Run with default server (test_db)
cargo run --bin mcp-dbtools

# Use release build
./target/release/mcp-dbtools prod_db

MCP Server Integration

Add to your MCP Server settings file:

macOS: ~/Library/Application Support/MCP Server/mcp_server_config.json Windows: %APPDATA%\MCP Server\mcp_server_config.json

{
  "mcpServers": {
    "db-tools-pocket": {
      "command": "cargo",
      "args": ["run", "--bin", "mcp-dbtools", "--", "test_db"],
      "cwd": "/path/to/mcp-dbtools",
      "env": {}
    }
  }
}

Or with pre-built binary:

{
  "mcpServers": {
    "db-tools-pocket": {
      "command": "/path/to/mcp-dbtools/target/release/mcp-dbtools",
      "args": ["test_db"],
      "env": {}
    }
  }
}

🧪 Testing

Test Database Connection

# Test database schema and data
cargo run --bin test_db

# Explore database content
cargo run --bin explore_data

Test MCP Server

# Test server with YAML config
cargo run --bin mcp-dbtools test_db

🔧 Configuration Options

🔒 Security Best Practices

1. Never hardcode sensitive data in YAML files
2. Use environment variables for passwords:

   password: "${DB_PASSWORD}"
   

3. Set appropriate file permissions on config files:

   chmod 600 ~/.mcp-dbtools/config.yml
   

4. Use read-only mode for production databases when possible

📊 Available SQL Operations

Through MCP Server, you can:

• Query tables: "Show me all records from the users table"
• Describe schema: "What columns does the products table have?"
• Run aggregations: "Calculate total sales by month"
• Join tables: "Join users and orders tables"
• Filter data: "Find all orders from last week"

🐛 Troubleshooting

Common Issues

1. "Failed to load YAML config"

   • Check if ~/.mcp-dbtools/config.yml exists
   • Verify YAML syntax is correct
   • Ensure environment variables are set

2. "Environment variable not found"

   • Set required environment variables before running
   • Check variable names match exactly (case-sensitive)

3. "Failed to connect to database"

   • Verify database is running
   • Check host, port, username, and password
   • Ensure database exists

4. "Server 'xyz' not found in config"

   • Check server name spelling in YAML file
   • Verify the server section exists under servers:

Debug Mode

Run with verbose output:

RUST_LOG=debug cargo run --bin mcp-dbtools test_db

🏗️ Development

Project Structure

mcp-dbtools/
├── src/
│   ├── main.rs          # MCP server entry point
│   ├── config.rs        # Configuration management
│   ├── test_db.rs       # Database testing utility
│   └── explore_data.rs  # Data exploration utility
├── mcp-rust-sdk/        # MCP SDK dependency
├── ~/.mcp-dbtools/      # Configuration directory
│   └── config.yml       # Database configurations
└── README.md

Building

# Development build
cargo build

# Release build
cargo build --release

# Run tests
cargo test

# Check code quality
cargo clippy
cargo fmt

📄 License

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🤝 Contributing

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📞 Support

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