mcp-server-postgresql: A PostgreSQL MCP Server

The Model Context Protocol (MCP) is an open protocol that enables seamless integration between LLM applications and external data sources and tools. Whether you're building an AI-powered IDE, enhancing a chat interface, or creating custom AI workflows, MCP provides a standardized way to connect LLMs with the context they need.

This repository is an example of how to create an MCP server for managing PostgreSQL databases.

Overview

A Model Context Protocol server for interacting with PostgreSQL. It provides tools for executing queries, creating tables, inserting rows of data, and retrieving results.

Components

Tools

The server implements the following tools:

• execute_query: Execute an arbitrary SQL query

  • Takes a query string
  • Returns results for SELECT-like statements, or a success message for others

• create_table: Create a new table

  • Takes a name and a schema (column definitions)
  • Creates the specified table

• insert_data: Insert a row of data into a table

  • Takes a table name and a data dict of column values
  • Inserts the specified row

• fetch_data: Fetch data by executing a SELECT query

  • Takes a query string
  • Returns matching rows as a result set

Configuration

The server connects to PostgreSQL using the following environment variables (all are required):

• PG_HOST: PostgreSQL host
• PG_PORT: PostgreSQL port
• PG_USER: PostgreSQL user
• PG_PASSWORD: PostgreSQL password
• PG_DATABASE: PostgreSQL database name

If any of these variables are missing, the server will raise an error during startup. Make sure to set each of these before running the server.

Quickstart

Claude Desktop

On MacOS: ~/Library/Application\ Support/Claude/claude_desktop_config.json
On Windows: %APPDATA%/Claude/claude_desktop_config.json

{
  "postgresql": {
    "command": "uvx",
    "args": [
      "mcp-server-postgresql"
    ]
  }
}

Development

Building and Publishing

To prepare the package for distribution:

1. Sync dependencies and update lockfile:

uv sync

2. Build package distributions:

uv build

This will create source and wheel distributions in the dist/ directory.

3. Publish to PyPI:

uv publish

Note: You'll need to set PyPI credentials via environment variables or command flags:

• Token: --token or UV_PUBLISH_TOKEN
• Or username/password: --username/UV_PUBLISH_USERNAME and --password/UV_PUBLISH_PASSWORD

Debugging

Since MCP servers run over stdio, debugging can be challenging. For the best debugging experience, we strongly recommend using the MCP Inspector.

You can launch the MCP Inspector via npm with this command:

npx @modelcontextprotocol/inspector uv --directory $(PWD) run mcp-server-postgresql

Upon launching, the Inspector will display a URL that you can access in your browser to begin debugging.