MCP PostgreSQL Server

A Model Context Protocol server that provides PostgreSQL database operations. This server enables AI models to interact with PostgreSQL databases through a standardized interface.

Installation

Manual Installation

npm install mcp-postgres-server

Or run directly with:

npx mcp-postgres-server

Configuration

The server requires the following environment variables:

{
  "mcpServers": {
    "postgres": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "mcp-postgres-server"],
      "env": {
        "PG_HOST": "your_host",
        "PG_PORT": "5432",
        "PG_USER": "your_user",
        "PG_PASSWORD": "your_password",
        "PG_DATABASE": "your_database"
      }
    }
  }
}

Available Tools

1. connect_db

Establish connection to PostgreSQL database using provided credentials.

use_mcp_tool({
  server_name: "postgres",
  tool_name: "connect_db",
  arguments: {
    host: "localhost",
    port: 5432,
    user: "your_user",
    password: "your_password",
    database: "your_database"
  }
});

2. query

Execute SELECT queries with optional prepared statement parameters. Supports both PostgreSQL-style ($1, $2) and MySQL-style (?) parameter placeholders.

use_mcp_tool({
  server_name: "postgres",
  tool_name: "query",
  arguments: {
    sql: "SELECT * FROM users WHERE id = $1",
    params: [1]
  }
});

3. execute

Execute INSERT, UPDATE, or DELETE queries with optional prepared statement parameters. Supports both PostgreSQL-style ($1, $2) and MySQL-style (?) parameter placeholders.

use_mcp_tool({
  server_name: "postgres",
  tool_name: "execute",
  arguments: {
    sql: "INSERT INTO users (name, email) VALUES ($1, $2)",
    params: ["John Doe", "john@example.com"]
  }
});

4. list_schemas

List all schemas in the connected database.

use_mcp_tool({
  server_name: "postgres",
  tool_name: "list_schemas",
  arguments: {}
});

5. list_tables

List tables in the connected database. Accepts an optional schema parameter (defaults to 'public').

// List tables in the 'public' schema (default)
use_mcp_tool({
  server_name: "postgres",
  tool_name: "list_tables",
  arguments: {}
});

// List tables in a specific schema
use_mcp_tool({
  server_name: "postgres",
  tool_name: "list_tables",
  arguments: {
    schema: "my_schema"
  }
});

6. describe_table

Get the structure of a specific table. Accepts an optional schema parameter (defaults to 'public').

// Describe a table in the 'public' schema (default)
use_mcp_tool({
  server_name: "postgres",
  tool_name: "describe_table",
  arguments: {
    table: "users"
  }
});

// Describe a table in a specific schema
use_mcp_tool({
  server_name: "postgres",
  tool_name: "describe_table",
  arguments: {
    table: "users",
    schema: "my_schema"
  }
});

Features

• Secure connection handling with automatic cleanup
• Prepared statement support for query parameters
• Support for both PostgreSQL-style ($1, $2) and MySQL-style (?) parameter placeholders
• Comprehensive error handling and validation
• TypeScript support
• Automatic connection management
• Supports PostgreSQL-specific syntax and features
• Multi-schema support for database operations

Security

• Uses prepared statements to prevent SQL injection
• Supports secure password handling through environment variables
• Validates queries before execution
• Automatically closes connections when done

Error Handling

The server provides detailed error messages for common issues:

• Connection failures
• Invalid queries
• Missing parameters
• Database errors

License

MIT