Gemini CLI Extension - MySQL

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 MySQL instances. It allows you to manage your databases, execute queries, and explore schemas directly from the Gemini CLI, using natural language prompts.

Important

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Why Use the MySQL Extension?

• Natural Language Management: Stop wrestling with complex commands. Explore schemas and query data by describing what you want in plain English.
• Seamless Workflow: As a Google-developed extension, it integrates seamlessly into the Gemini CLI environment. No need to constantly switch contexts 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 MySQL instance.
• A user with 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/mysql

Claude Code

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

Codex

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

Antigravity

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

See Configuration for how each harness supplies the connection settings.

Configuration

The plugin connects to MySQL using these settings:

• MYSQL_HOST: (Optional) The MySQL host. Defaults to localhost.
• MYSQL_PORT: (Optional) The MySQL port. Defaults to 3306.
• MYSQL_DATABASE: The name of the database to connect to.
• MYSQL_USER: The database username.
• MYSQL_PASSWORD: The password for the database user.

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 mysql [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 MYSQL_HOST="<your-mysql-host>"       # Optional, defaults to localhost
export MYSQL_PORT="<your-mysql-port>"       # Optional, defaults to 3306
export MYSQL_DATABASE="<your-database-name>"
export MYSQL_USER="<your-database-user>"
export MYSQL_PASSWORD="<your-database-password>"

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 MySQL 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 and descriptions.
• execute_sql: Use this tool to execute any SQL statement.
• get_query_plan: Use this tool to generate an execution plan.
• list_active_queries: Use this tool to lists top N (default 10) ongoing queries.
• list_tables_missing_unique_indexes: Use this tool to find tables that do not have primary or unique key constraint
• list_table_fragmentation: Use this tool to list fragmented tables

Additional Extensions

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

• Cloud SQL for MySQL 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.