Google just shipped one of the more consequential pieces of its agent stack to the public. Managed Agents in the Gemini API are now available, turning what used to be weeks of sandbox plumbing into a single HTTP call. A single call now spins up an agent that reasons, uses tools and executes code in an isolated, ephemeral Linux environment, powered by the new Antigravity agent built on Gemini 3.5 Flash and available via the Interactions API and in Google AI Studio.

The pitch is simple: stop building agent infrastructure and start building agent behavior. Building a production-grade agent used to mean managing complex infrastructure, scaffolding and managing isolated sandboxes to serve customers as you prepare to scale. With Gemini Managed Agents, Google is abstracting away the complexity so you can focus on your product experience and agent behavior.

What actually ships when you make the call

Each call to the Antigravity agent provisions a remote Linux environment. Within that environment, the agent can plan tasks, call tools, and execute code. It can also manage files and browse the web to retrieve current information. Each interaction can create or receive an environment. That last bit matters more than it sounds: each interaction creates or receives an environment, which you can use in follow-up calls to resume the session with all files and state intact.

Anyone who has built an agent loop on top of a stateless code interpreter knows the pain this removes. In the past, code interpreter-like functions would restart a container with each call, losing all previously pip installed packages, written files, and history. Now the filesystem, installed dependencies, and conversation state live server-side between turns.

The two-API split

The surface area is intentionally small. The Interactions API is the runtime interface: send a task, get back an agent that reasons and acts. The Agents API is the control plane: define, register, and manage named agents with custom instructions, tools, skills, and environment configurations. In practice that means you register an agent once, then hit the runtime endpoint every time a user message comes in.