Gemini API Managed Agents: 3.6 Flash, hooks, and more

Google announced updates to Managed Agents in the Gemini API on Monday, adding environment hooks, model selection, free tier access, budget controls, and scheduled triggers. The company said the capabilities build on a previous release that introduced background tasks and remote MCP server integration. The antigravity-preview-05-2026 agent now runs Gemini 3.6 Flash by default without requiring code changes. Developers can explicitly select models such as Gemini 3.5 Flash or Gemini 3.5 Flash-Lite by passing agent_config.model when creating an interaction. Environment hooks allow users to run custom scripts before or after every tool call inside the sandbox using a .agents/hooks.json configuration file. Hooks support regular expression matchers and can execute command or HTTP type handlers. Managed agents are now available on free tier projects, allowing developers to experiment without active billing. Budget controls include a max_total_tokens parameter to cap total token consumption, pausing execution safely when the limit is reached while preserving environment state. Scheduled triggers automate recurring agent tasks with cron schedules, reusing the same sandbox so files persist across executions. The Environments API lets users list, inspect, and delete sandbox sessions from code.