MCP Datalink

🚀 @pilat/mcp-datalink

MCP server for PostgreSQL, MySQL, and SQLite. Enables AI assistants to securely access databases via Model Context Protocol.

npx @pilat/mcp-datalink

It is compatible with Claude Desktop, Claude Code, Cursor, Cline, and any MCP-compatible client.

🚀 Quick Start

npx @pilat/mcp-datalink

📦 Installation

Add the following to your MCP client config file (see config locations below):

{
  "mcpServers": {
    "datalink": {
      "command": "npx",
      "args": ["-y", "@pilat/mcp-datalink"],
      "env": {
        "DATALINK_ANALYTICS_URL": "postgresql://user:password@localhost:5432/analytics",
        "DATALINK_ANALYTICS_READONLY": "true",

        "DATALINK_INVENTORY_URL": "mysql://user:password@localhost:3306/inventory",

        "DATALINK_CACHE_URL": "sqlite:///path/to/cache.db"
      }
    }
  }
}

This configuration creates three database connections: analytics (read-only), inventory, and cache.

Configuration Variables

Connection URL Formats

# PostgreSQL
postgresql://user:password@localhost:5432/dbname
postgresql://user:password@localhost:5432/dbname?sslmode=require

# MySQL
mysql://user:password@localhost:3306/dbname
mysql://user:password@localhost:3306/dbname?ssl=true

# SQLite
sqlite:///path/to/database.db
sqlite:///Users/me/data/app.sqlite
sqlite://../relative/path/data.db

Environment Variable Substitution

URLs support the ${VAR} syntax to reference other environment variables:

{
  "mcpServers": {
    "datalink": {
      "command": "npx",
      "args": ["-y", "@pilat/mcp-datalink"],
      "env": {
        "DATALINK_MAIN_URL": "${DATABASE_URL}"
      }
    }
  }
}

This allows you to reuse existing environment variables (such as DATABASE_URL from your shell or .env file).

Supported Syntax

Examples

# Reference an existing DATABASE_URL
DATALINK_MAIN_URL="${DATABASE_URL}"

# Build a URL from parts
DATALINK_MAIN_URL="postgresql://${DB_USER}:${DB_PASS}@${DB_HOST}:5432/mydb"

# With default values
DATALINK_MAIN_URL="postgresql://localhost:${DB_PORT:-5432}/mydb"

Config File Locations

💻 Tools

🔧 Security

• Only prepared statements are used (prevents SQL injection).
• Each query contains a single statement (no chaining).
• DDL operations are blocked (no DROP, ALTER, TRUNCATE).
• Read-only mode can be set for each connection.
• There is a response size limit (default: 100 rows, 64KB, configurable via DATALINK_MAX_TOTAL_SIZE).
• Query timeout: default is 30 seconds, the model can request up to 10 minutes, and MAX_TIMEOUT sets an upper limit.

📄 License

MIT