Orchestrator pairs Carbon and Hydrogen in Antigravity

Google has opened Orchestrator in Antigravity, a model option that pairs Gemini 4 Carbon with Gemini 4 Hydrogen in one session. It is rolling out today to Google AI Ultra subscribers. Enterprises can use it in Gemini for business, and more models and plans are planned.

Carbon can plan the task. Hydrogen can write the edits and run the tests. Carbon can start in a read-only pass, mapping dependencies and setting points where the plan should be rebuilt. Hydrogen can then write the edits, update packages, and run tests. If that work stalls, it goes back to Carbon to inspect the state and resume.

On one test it used 24 percent less quota and finished 19 percent faster. On Terminal-Bench 4.1, Orchestrator reached a success rate near Carbon's, on average, while using 24 percent less quota and finishing 19 percent faster. That figure is an average on that test.

A static router sends the whole task to one model. Orchestrator switches between the two as the task changes, including steps that only become clear after the work has started. The point is to keep a frontier model off routine edits.

Teams can also assign the models by hand. The Antigravity SDK can put Hydrogen on triage, fast edits, and interface changes, and put Carbon on larger refactors and security checks. Orchestrator itself is the automatic version of that split, chosen from the model menu.

Hydrogen is also in Antigravity on its own. Orchestrator is the paired option. It does not replace Carbon or Hydrogen as separate choices in the same menu.