Gemini CLI Extension - PostgreSQL

Note

This extension is currently in beta (pre-v1.0), and may see breaking changes until the first stable release (v1.0).

This Gemini CLI extension provides a set of tools to interact with PostgreSQL instances. It allows you to manage your databases, execute queries, and explore schemas directly from the Gemini CLI, using natural language prompts.

Learn more about Gemini CLI Extensions.

Important

We Want Your Feedback! Please share your thoughts with us by filling out our feedback form. Your input is invaluable and helps us improve the project for everyone.

Why Use the Postgres Extension?

• Natural Language Management: Stop wrestling with complex commands. Explore schemas and query data by describing what you want in plain English.
• Seamless Workflow: Stay in your CLI. No need to constantly switch contexts to the GCP console for common database tasks.
• Code Generation: Accelerate development by asking Gemini to generate data classes and other code snippets based on your table schemas.

Prerequisites

Before you begin, ensure you have the following:

• One of the supported agent harnesses, installed and authenticated:
  • Gemini CLI (v0.6.0+)
  • Claude Code
  • Codex
  • Antigravity CLI
• Node.js (the MCP server runs via npx).
• A running PostgreSQL instance.
• Users are granted database-level permissions to execute queries.

Getting Started

Installation

All harnesses use the same plugin; the MCP server runs via npx (no binary to download). Install with your harness of choice:

Gemini CLI

gemini extensions install https://github.com/gemini-cli-extensions/postgres

Claude Code

claude plugin marketplace add gemini-cli-extensions/postgres
claude plugin install postgres@postgres

Codex

codex plugin marketplace add gemini-cli-extensions/postgres
codex plugin add postgres@postgres

Antigravity

agy plugin install https://github.com/gemini-cli-extensions/postgres

See Configuration for how each harness supplies the connection settings.

Configuration

The plugin connects to PostgreSQL using these settings:

• POSTGRES_DATABASE: The name of the database to connect to.
• POSTGRES_USER: The database username.
• POSTGRES_PASSWORD: The password for the database user.
• POSTGRES_HOST: (Optional) The Postgres host. Defaults to localhost.
• POSTGRES_PORT: (Optional) The Postgres port. Defaults to 5432.
• POSTGRES_QUERY_PARAMS: (Optional) Connection string parameters.

How you supply them depends on the harness:

• Gemini CLI: prompted on install and saved to the extension's .env. View or update later with gemini extensions list / gemini extensions config postgres [setting] [--scope user|workspace] (restart the CLI to apply).
• Claude Code: pass --config KEY=VALUE on install (repeatable), or run /plugin inside Claude Code.
• Codex and Antigravity: export the variables in your shell before starting:

export POSTGRES_DATABASE="<your-database-name>"
export POSTGRES_USER="<your-database-user>"
export POSTGRES_PASSWORD="<your-database-password>"
export POSTGRES_HOST="<your-postgres-host>"                    # Optional, defaults to localhost
export POSTGRES_PORT="<your-postgres-port>"                    # Optional, defaults to 5432
export POSTGRES_QUERY_PARAMS="<your-connection-string-params>" # Optional

Note

See Troubleshooting for debugging your configuration.

Start Gemini CLI

To start the Gemini CLI, use the following command:

gemini

Warning

Changing Instance & Database Connections Currently, the database connection must be configured before starting the Gemini CLI and can not be changed during a session. To save and resume conversation history use command: /chat save <tag> and /chat resume <tag>.

Usage Examples

Interact with Postgres using natural language right from your IDE:

• Explore Schemas and Data:

  • "Show me all tables in the 'orders' database."
  • "What are the columns in the 'products' table?"
  • "How many orders were placed in the last 30 days, and what were the top 5 most purchased items?"

• Generate Code:

  • "Generate a Python dataclass to represent the 'customers' table."

Supported Tools

• list_tables: Use this tool to list tables in the database.
• database_overview: Use this tool to fetches the current state of the PostgreSQL server.
• execute_sql: Use this tool to execute a SQL query.
• list_active_queries: Use this tool to list currently running queries.
• list_available_extensions: Use this tool to list available extensions for installation.
• list_installed_extensions: Use this tool to list installed extensions.
• get_query_plan: Use this tool to get query plan.
• list_autovacuum_configurations: Use this tool to list autovacuum configurations and its value.
• list_database_stats: Use this tool to lists the key performance and activity statistics for each database in the PostgreSQL server.
• list_indexes: Use this tool to list available user indexes in a PostgreSQL database.
• list_memory_configurations: Use this tool to list memory configurations and its value.
• list_pg_settings: Use this tool to list configuration parameters for the PostgreSQL server.
• list_publication_tables: Use this tool to list publication tables in a PostgreSQL database.
• list_replication_slots: Use this tool to list replication slots.
• list_roles: Use this tool to lists all the user-created roles in PostgreSQL database.
• list_schemas: Use this tool to lists schemas in the database.
• list_sequences: Use this tool to list sequences in a PostgreSQL database.
• list_tablespaces: Use this tool to lists tablespaces in the database.
• list_top_bloated_tables: Use this tool to list top bloated tables.
• list_triggers: Use this tool to lists triggers in the database.
• list_views: Use this tool to lists views in the database from pg_views with a default limit of 50 rows.
• list_invalid_indexes: Use this tool to list invalid indexes.

Additional Extensions

Find additional extensions to support your entire software development lifecycle at github.com/gemini-cli-extensions, including:

• Cloud SQL for PostgreSQL extension
• and more!

Troubleshooting

Use gemini --debug to enable debugging.

Common issues:

• "✖ Error during discovery for server: MCP error -32000: Connection closed": The database connection has not been established. Ensure your configuration is set via environment variables.
• "✖ MCP ERROR: Error: spawn npx ENOENT": Node.js/npx is not installed or not on your PATH. Install Node.js (which provides npx).
• "npm error"/network failures on first run: npx fetches @toolbox-sdk/server on first launch, so it needs network access. Retry once connectivity is available.