Hooks

Hooks let you run custom scripts or external HTTP requests right before or after the agent executes code or modifies files inside its remote sandbox. Use hooks to extend the agent loop with automated guardrails and background workflows, such as:

  • Enforcing safety and access guardrails before high-risk shell commands or restricted file reads execute.
  • Automating data pipeline transformations right after an agent creates or modifies files.

  • Streaming enterprise audit telemetry to external monitoring systems after tool execution.

Python

import json
from google import genai

client = genai.Client()

hooks_config = {
    "security-gate": {
        "pre_tool_execution": [
            {
                "matcher": "code_execution",
                "hooks": [
                    {
                        "type": "command",
                        "command": "python3 /.agents/hooks-scripts/gate.py",
                        "timeout": 10,
                    }
                ],
            }
        ]
    }
}

gate_script = """#!/usr/bin/env python3
import sys, json
data = json.load(sys.stdin)
cmd = str(data.get("tool_call", {}).get("args", {}))
if "rm -rf" in cmd:
    print(json.dumps({"decision": "deny", "reason": "Destructive command blocked by security gate."}))
else:
    print(json.dumps({"decision": "allow"}))
"""

interaction = client.interactions.create(
    agent="antigravity-preview-05-2026",
    input="Run `rm -rf /tmp/forbidden` using code_execution.",
    tools=[{"type": "code_execution"}],
    environment={
        "type": "remote",
        "sources": [
            {
                "type": "inline",
                "target": ".agents/hooks.json",
                "content": json.dumps(hooks_config, indent=2),
            },
            {
                "type": "inline",
                "target": ".agents/hooks-scripts/gate.py",
                "content": gate_script,
            },
        ],
    },
)
print(interaction.output_text)

JavaScript

import { GoogleGenAI } from "@google/genai";

const client = new GoogleGenAI({});

const hooksConfig = {
    "security-gate": {
        pre_tool_execution: [
            {
                matcher: "code_execution",
                hooks: [
                    {
                        type: "command",
                        command: "python3 /.agents/hooks-scripts/gate.py",
                        timeout: 10,
                    },
                ],
            },
        ],
    },
};

const gateScript = `#!/usr/bin/env python3
import sys, json
data = json.load(sys.stdin)
cmd = str(data.get("tool_call", {}).get("args", {}))
if "rm -rf" in cmd:
    print(json.dumps({"decision": "deny", "reason": "Destructive command blocked by security gate."}))
else:
    print(json.dumps({"decision": "allow"}))
`;

const interaction = await client.interactions.create({
    agent: