# Antigravity Features and Practical Usage 🚀 What if you could inject your own logic into an agent's execution loop? Antigravity's lifecycle hooks let you enforce policy, log everything, and add guardrails automatically. 📌 Title and Feature URL Title: Hooks URL: 📝 Overview Hooks let you run custom scripts or shell commands at specific points in Antigravity's agent execution loop. By reacting to events such as before/after a tool call or at session termination, you can enforce rules, capture diagnostics, and add guardrails without relying on a human to watch every step. They are the foundation for making agents follow your organization's policies. 🔧 How It Works Hooks fire on lifecycle events and differ by their nature: - PreToolUse: fires before a tool runs, letting you inspect arguments and allow or deny the call - PostToolUse: fires after a tool completes, useful for logging and audit - PreInvocation: fires before the model is called - PostInvocation: fires immediately after each model invocation completes - Stop: fires when the execution loop ends - By behavior, hooks fall into Inspect (read-only, non-blocking), Decide (read-only, blocking allow/deny), and Transform (can modify data) - Decide hooks return a decision result (HookResult) with allow/deny to stop policy violations before they happen 🛠 Practical Usage - Use PreToolUse to inspect risky command arguments and return deny to halt execution - Use PostToolUse to emit structured logs and build metrics or audit trails - Inject system instructions before a model call to apply internal guidelines to the prompt - Use Stop as a stop-condition check to force tests or lint to pass - Execution order is Decide -> operation -> Inspect, validating first to avoid TOCTOU-style gaps 🎯 Use Cases - Block destructive operations against a production DB before the agent runs them - Auto-generate an audit log by recording every tool call for later review - Inject coding standards and prohibited actions before each model call - Force lint, type checks, and tests to run at session termination ⚠️ Caveats - Inspect and Decide hooks are read-only and cannot mutate data (use Transform hooks for that) - Faulty deny logic can stop legitimate work, so design conditions carefully - The config location and JSON I/O contract may vary by version or distribution, so confirm with the latest docs - Hooks interrupt the loop, so heavy work inside them slows overall responsiveness #Antigravity# #DevTools#