PostgreSQL MCP

Read-only Model Context Protocol server for PostgreSQL. Gives LLM agents safe SQL access: schema discovery, table metadata, and SELECT queries inside READ ONLY transactions.

Built as a maintained alternative to the deprecated @modelcontextprotocol/server-postgres package.

Features

• query — read-only SQL (SELECT, WITH, EXPLAIN, SHOW) with row caps

• list_tables — list tables in a schema

• describe_table — column names, types, nullability, defaults

• Resources — per-table schema JSON via MCP resources

• Safety — SQL keyword guard + BEGIN READ ONLY transactions

• Config — connection string via CLI arg or DATABASE_URL / MCP_POSTGRES_URL

Related MCP server: PostgreSQL MCP Server

Quick start

git clone https://github.com/vallaksa/postgresql-mcp.git
cd postgresql-mcp
npm install
npm run build

Run with a connection string:

export DATABASE_URL="postgresql://mcp_reader:password@localhost:5432/devstrom"
npm start

Or pass the URL as the first argument:

node dist/index.js "postgresql://mcp_reader:password@localhost:5432/devstrom"

Cursor / Claude Desktop

Add to .cursor/mcp.json or Claude config:

{
  "mcpServers": {
    "postgresql": {
      "command": "node",
      "args": [
        "/absolute/path/to/postgresql-mcp/dist/index.js",
        "postgresql://mcp_reader:password@localhost:5432/devstrom"
      ]
    }
  }
}

After publishing to npm:

{
  "mcpServers": {
    "postgresql": {
      "command": "npx",
      "args": ["-y", "postgresql-mcp", "postgresql://mcp_reader:password@localhost:5432/devstrom"]
    }
  }
}

Read-only database user

Create a dedicated reader (example for Dev-Strom):

psql -U postgres -d devstrom -f scripts/setup_readonly_user.sql

Set MCP_READER_PASSWORD before running the script.

Environment variables

Dev-Strom integration

In Dev-Strom, point scripts/start_mcp.sh at this server and set MCP_POSTGRES_URL in .env.

Development

npm test
npm run typecheck
npm run dev -- "postgresql://..."

License

MIT