MCP Server Postgres Multi Schema

🚀 PostgreSQL Multi-Schema MCP Server

A Model Context Protocol (MCP) server that provides read-only access to PostgreSQL databases with enhanced multi-schema support. This server enables Large Language Models (LLMs) to examine the database schema across multiple namespaces and execute read-only queries while maintaining schema isolation.

✨ Features

• Multi-Schema Support: Explicitly specify which schemas to expose via command-line configuration.
• Schema Isolation: Enforce strict access control, limiting access to only the authorized schemas listed at server startup.
• Cross-Schema Discovery: Provide a consistent view of tables across multiple schemas while maintaining schema boundaries.
• Metadata Security: Filter system catalogs to display only user-defined tables within the specified schemas.

📦 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.
  • Maintain schema context through search path restrictions.

Resources

The server provides schema information for each table in the authorized schemas:

• Table Schema (postgres://<host>/<db_schema>/<table>/schema)
  • JSON schema information for each table.
  • Includes column names, data types, and type modifiers.
  • Automatically discovered from database metadata.
  • Supports multiple schemas with an explicit schema allowlist.

💻 Usage Examples

Basic Usage

The server requires a database URL and accepts a comma-separated list of schemas to expose:

npx -y mcp-server-postgres-multi-schema <database-url> [schemas]

• database-url: PostgreSQL connection string (e.g., postgresql://localhost/mydb).
• schemas: A comma-separated list of schemas to expose (default is 'public' if not specified).

Advanced Usage

# Connect using the default public schema
npx -y mcp-server-postgres-multi-schema postgresql://localhost/mydb

# Use multiple schemas
npx -y mcp-server-postgres-multi-schema postgresql://localhost/mydb public,analytics,staging

📚 Documentation

Configuration with Claude Desktop

Configure the "mcpServers" section in your claude_desktop_config.json:

{
  "mcpServers": {
    "postgres": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-server-postgres-multi-schema",
        "postgresql://localhost/mydb",
        "public,audit"
      ]
    }
  }
}

📄 License

This multi-schema MCP server is released under the MIT License. You may use, modify, and distribute the software under the terms described in the LICENSE file.