What is Mcp Pg Schema

mcp-pg-schema is an MCP server designed to provide read-only access to PostgreSQL databases, allowing LLMs to inspect database schemas and execute read-only queries.

Use cases

Use cases include querying database schemas for data exploration, integrating with LLMs for enhanced data insights, and supporting applications that require secure read-only access to database information.

How to use

To use mcp-pg-schema, configure it in the ‘mcpServers’ section of your ‘claude_desktop_config.json’ file, either using Docker or NPX to run the server with the appropriate PostgreSQL connection string.

Key features

Key features include executing read-only SQL queries, providing JSON schema information for each table, and automatically discovering metadata from the database.

Where to use

mcp-pg-schema can be used in applications requiring database schema inspection and read-only data retrieval, particularly in data analysis, machine learning, and application development.

PostgreSQL

A Model Context Protocol server that provides read-only access to PostgreSQL databases. This server enables LLMs to inspect database schemas and execute read-only queries.

Components

Tools

• query
  • Execute read-only SQL queries against the connected database
  • Input: sql (string): The SQL query to execute
  • All queries are executed within a READ ONLY transaction

Resources

The server provides schema information for each table in the database:

• Table Schemas (postgres://<host>/<table>/schema)
  • JSON schema information for each table
  • Includes column names and data types
  • Automatically discovered from database metadata

Usage with Claude Desktop

To use this server with the Claude Desktop app, add the following configuration to the “mcpServers” section of your claude_desktop_config.json:

Docker

• when running docker on macos, use host.docker.internal if the server is running on the host network (eg localhost)
• username/password can be added to the postgresql url with postgresql://user:password@host:port/db-name

{
  "mcpServers": {
    "postgres": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "mcp/postgres",
        "postgresql://host.docker.internal:5432/mydb"
      ]
    }
  }
}

NPX

{
  "mcpServers": {
    "postgres": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-postgres",
        "postgresql://localhost/mydb"
      ]
    }
  }
}

Replace /mydb with your database name.

Building

Docker:

docker build -t mcp/postgres -f src/postgres/Dockerfile . 

License

This MCP server is licensed under the MIT License. This means you are free to use, modify, and distribute the software, subject to the terms and conditions of the MIT License. For more details, please see the LICENSE file in the project repository.