Postgres Query MCP server

This MCP Postgres Query Server implements the Model Context Protocol to provide a secure, read-only interface to PostgreSQL databases. It's designed specifically to work with Claude Desktop and other MCP clients, allowing you to safely execute SQL queries with validation and timeout protection.

Installation

Prerequisites

• Node.js (v14 or later)
• npm (comes with Node.js)
• PostgreSQL database (connection details required)

Setup Instructions

# Clone the repository
git clone https://github.com/RathodDarshil/mcp-postgres-query-server.git
cd mcp-postgres-query-server

# Install dependencies
npm install

# Build the project
npm run build

Configuration with Claude Desktop

Adding the Server to Claude Desktop

1. Open Claude Desktop
2. Navigate to Settings > Developer > Edit Config
3. Add the postgres-query-server to the mcpServers section:

{
    "mcpServers": {
        "postgres-query": {
            "command": "node",
            "args": [
                "/path/to/your/mcp-postgres-query-server/dist/index.js",
                "postgresql://username:password@hostname:port/database"
            ]
        }
    }
}

Configuration Example

Here's a complete example of a configuration file:

{
    "mcpServers": {
        "postgres-query": {
            "command": "node",
            "args": [
                "/Users/darshilrathod/mcp-servers/mcp-postgres-query-server/dist/index.js",
                "postgresql://user:password@localhost:5432/mydatabase"
            ]
        }
    }
}

Applying Configuration Changes

After updating your configuration:

1. Save the configuration file
2. Restart Claude Desktop
3. The MCP server should now appear in the MCP server selection dropdown in Settings

Using the Server

Available Tools

query-postgres

This tool executes read-only SQL queries against your PostgreSQL database.

Parameters:

• query (string): A SQL SELECT query to execute

Response:

• JSON object containing:
  • rows: The result set rows
  • rowCount: Number of rows returned
  • fields: Column metadata

Example Usage

To query your database within Claude Desktop, use:

query-postgres: SELECT * FROM users LIMIT 5

Features and Security

Key Features

• Read-Only Access: Only SELECT queries are allowed
• Query Validation: Prevents harmful SQL operations
• Timeout Protection: Queries running longer than 10 seconds are automatically terminated
• Structured Results: Query results returned in JSON format

Security Measures

• Strict validation ensures only read-only queries are executed
• Connection to the database uses SSL when available
• Query timeout prevents resource exhaustion
• No write operations are permitted

How to add this MCP server to Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > MCP and click "Add new global MCP server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "cursor-rules-mcp": {
            "command": "npx",
            "args": [
                "-y",
                "cursor-rules-mcp"
            ]
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explictly ask the agent to use the tool by mentioning the tool name and describing what the function does.