PostgreSQL MCP Server

A PostgreSQL MCP server implementation using the Model Context Protocol (MCP) Python SDK- an open protocol that enables seamless integration between LLM applications and external data sources. This server allows AI agents to interact with PostgreSQL databases through a standardized interface.

Features

List database schemas
List tables within schemas
Describe table structures
List table constraints and relationships
Get foreign key information
Execute SQL queries

Quick Start

# Run the server without a DB connection (useful for Glama or inspection)
python postgres_server.py

# With a live database – pick one method:
export POSTGRES_CONNECTION_STRING="postgresql://user:pass@host:5432/db"
python postgres_server.py

# …or…
python postgres_server.py --conn "postgresql://user:pass@host:5432/db"

# Or using Docker (build once, then run):
# docker build -t mcp-postgres . && docker run -p 8000:8000 mcp-postgres

Installation

Installing via Smithery

To install PostgreSQL MCP Server for Claude Desktop automatically via Smithery:

npx -y @smithery/cli install @gldc/mcp-postgres --client claude

Manual Installation

Clone this repository:

git clone <repository-url>
cd mcp-postgres

Create and activate a virtual environment (recommended):

python -m venv venv
source venv/bin/activate  # On Windows, use: venv\Scripts\activate

Install dependencies:

pip install -r requirements.txt

Usage

Start the MCP server.

# Without a connection string (server starts, DB‑backed tools will return a friendly error)
python postgres_server.py

# Or set the connection string via environment variable:
export POSTGRES_CONNECTION_STRING="postgresql://username:password@host:port/database"
python postgres_server.py

# Or pass it using the --conn flag:
python postgres_server.py --conn "postgresql://username:password@host:port/database"

The server provides the following tools:

query: Execute SQL queries against the database
list_schemas: List all available schemas
list_tables: List all tables in a specific schema
describe_table: Get detailed information about a table's structure
get_foreign_keys: Get foreign key relationships for a table
find_relationships: Discover both explicit and implied relationships for a table

Running with Docker

Build the image:

docker build -t mcp-postgres .

Run the container without a database connection (the server stays inspectable):

docker run -p 8000:8000 mcp-postgres

Run with a live PostgreSQL database by supplying POSTGRES_CONNECTION_STRING:

docker run \
  -e POSTGRES_CONNECTION_STRING="postgresql://username:password@host:5432/database" \
  -p 8000:8000 \
  mcp-postgres

If the environment variable is omitted, the server boots normally and all database‑backed tools return a friendly “connection string is not set” message until you provide it.

Configuration with mcp.json

To integrate this server with MCP-compatible tools (like Cursor), add it to your ~/.cursor/mcp.json:

{
  "servers": {
    "postgres": {
      "command": "/path/to/venv/bin/python",
      "args": [
        "/path/to/postgres_server.py"
      ],
      "env": {
        "POSTGRES_CONNECTION_STRING": "postgresql://username:password@host:5432/database?ssl=true"
      }
    }
  }
}

If POSTGRES_CONNECTION_STRING is omitted, the server still starts and is fully inspectable; database‑backed tools will simply return an informative error until the variable is provided.

Replace:

/path/to/venv with your virtual environment path
/path/to/postgres_server.py with the absolute path to the server script

Security

Never expose sensitive database credentials in your code
Use environment variables or secure configuration files for database connection strings
Consider using connection pooling for better resource management
Implement proper access controls and user authentication

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

PostgreSQL Database