Tailor Gemini CLI to your workflow with hooks

This post introduces Gemini CLI hooks, a mechanism to customize the AI agent's behavior by running scripts at predefined lifecycle points without modifying its source code.

• •Hooks act as synchronous middleware within the agent loop, enabling context injection, action validation, policy enforcement, and tool usage logging
• •BeforeTool hooks can intercept file write operations to detect and block secrets like API keys or AWS credentials using regex pattern matching
• •Hook scripts receive structured JSON input via stdin and return decisions (allow/deny) with an optional reason and system message for agent self-correction
• •The matcher property (e.g., "write_file|replace") limits hook execution to specific tools, keeping the agent loop fast and targeted
• •Gemini CLI extensions can bundle hooks directly, enabling features like the Ralph loop—an AfterAgent hook that forces continuous iterative execution until a task is complete