Postgres MCP Server

A Model Context Protocol (MCP) server that provides secure database access to PostgreSQL through Kysely ORM. This server enables Claude Desktop to interact with PostgreSQL databases using natural language.

Features

• MCP Tools: Query execution, table listing, schema inspection, and constraint information
• Type Safety: Full TypeScript support with typed inputs/outputs
• Connection Pooling: Configurable connection limits with idle timeout
• Error Handling: Graceful error messages for connection and query issues
• Security: Parameterized queries to prevent SQL injection

Installation

npx postgres-mcp-server

Configuration

Create a .env file with your database credentials:

DB_HOST=127.0.0.1
DB_PORT=5432
DB_USER=postgres
DB_PASSWORD=your_password_here
DB_NAME=postgres
DB_SSL=true

Available Tools

| Tool | Description | Required Parameters | Optional Parameters | | --------------------- | ------------------------------------------- | ----------------------------------- | ----------------------------------------------------------- | | query | Execute SQL queries with pagination support | sql (string) | pageSize (1-500), offset (number), parameters (array) | | describe_table | Get table structure and column details | schema (string), table (string) | - | | list_tables | List all tables in a schema | schema (string) | - | | list_schemas | List all schemas in the database | - | includeSystemSchemas (boolean) | | get_constraints | Get table constraints (PK, FK, etc.) | schema (string), table (string) | - | | list_indexes | List indexes for a table or schema | schema (string) | table (string) | | list_views | List views in a schema | schema (string) | - | | list_functions | List functions and procedures | schema (string) | - | | explain_query | Get query execution plan | sql (string) | analyze (boolean), format (text/json/xml/yaml) | | get_table_stats | Get table size and statistics | schema (string) | table (string) |

Key Features

• Pagination: Query tool supports up to 500 rows per page with automatic LIMIT/OFFSET handling
• Security: Parameterized queries prevent SQL injection, READ_ONLY mode by default
• Type Safety: Full TypeScript support with Zod schema validation

Claude Desktop Configuration

Add this server to your Claude Desktop configuration file:

Edit claude_desktop_config.json:

{
  "mcpServers": {
    "postgres-mcp-server": {
      "command": "npx",
      "args": ["postgres-mcp-server"],
      "env": {
        "DB_HOST": "127.0.0.1",
        "DB_PORT": "5432",
        "DB_USER": "postgres",
        "DB_PASSWORD": "your_password_here",
        "DB_NAME": "your_database_name",
        "DB_SSL": "true"
      }
    }
  }
}

Configuration File Locations

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

Development

# Clone and install dependencies
git clone https://github.com/abiswas97/postgres-mcp-server.git
cd postgres-mcp-server
npm install

# Run in development mode with hot reload
npm run dev

# Build for production
npm run build

# Run tests
npm run test

# Run specific test suites
npm run test:unit
npm run test:integration

Environment Variables

| Variable | Default | Description | | ------------------- | ----------- | --------------------------------------- | | DB_HOST | 127.0.0.1 | PostgreSQL host | | DB_PORT | 5432 | PostgreSQL port | | DB_USER | postgres | Database user | | DB_PASSWORD | required | Database password | | DB_NAME | postgres | Database name | | DB_SSL | true | Enable SSL connection | | READ_ONLY | true | Restrict to SELECT/WITH/EXPLAIN queries | | QUERY_TIMEOUT | 30000 | Query timeout in milliseconds | | MAX_PAGE_SIZE | 500 | Maximum rows per page | | DEFAULT_PAGE_SIZE | 100 | Default page size when not specified |

License

ISC