Google Antigravity adds Orchestrator, which dynamically switches between models like Carbon and Hydrogen within the same session, for AI Ultra subscribers (Google Antigravity)

Google has introduced Gemini 4 Hydrogen alongside a new model dropdown named Orchestrator within the Google Antigravity platform. This new feature combines Hydrogen with Gemini 4 Carbon, striking a balance between quality, efficiency, and latency.

Previously, Google unveiled Gemini 4 Carbon, designed to handle large-scale, multi-worktree engineering tasks with the aid of parallel agent teams. Since its launch, tens of thousands of swarms have been initiated on Antigravity, demonstrating the platform's capability to advance intelligence on complex problems.

However, running frontier reasoning models with multiple parallel agents during everyday feature work and debugging slows down the loop and exhausts frontier quota. As a result, a common industry approach is to use a static model router that assumes task difficulty based on the first prompt and routes the task to the most cost-effective model capable of completing it. This approach, however, becomes ineffective as agents become longer-running and require varying levels of complexity at different stages of the task.

To address this issue, Google presents Orchestrator, a dynamic, bidirectional model that switches between Carbon and Gemini 4 Hydrogen throughout the lifecycle of a single task. For instance, Carbon can commence in a read-only phase to investigate dependencies, clarify uncertainties, and formulate a comprehensive plan that includes explicit re-planning triggers.

Subsequently, Hydrogen can take over to execute edits, update packages, and run tests. If Hydrogen encounters any difficulties, it can revert back to Carbon for state inspection, plan repair, and resumption of execution. This mechanism enables Orchestrator to achieve near-Carbon task success rates while being faster and more quota-efficient.

On Terminal-Bench 4.1, Orchestrator has reached near-Carbon task success rates, consuming, on average, 24% less quota and completing tasks 19% faster. Gemini 4 Hydrogen offers cutting-edge intelligence for routine coding and agentic workflows. By integrating both Gemini 4 Carbon and Gemini 4 Hydrogen behind a single prompt, Orchestrator provides users with the capability to avail both models within a single prompt.

Starting today, Gemini 4 Hydrogen is rolled out across Google AI Pro and Ultra subscribers. Orchestrator is currently available for Google AI Ultra subscribers, with plans to support additional models and plans in the future. Enterprises can access both Gemini 4 Carbon and Hydrogen through Gemini for business.