Google Rolls Out Orchestrator in Antigravity, Pairing Gemini 4 Carbon as Planner With Hydrogen as Executor
We’re rolling out Orchestrator in @Antigravity to Google AI Ultra subscribers, letting you run multiple models in a single session instead of routing the entire task to one model. Orchestrator pairs a frontier model with a fast execution model: Carbon sets the plan, hands off code edits and testing to Hydrogen, and steps back in to repair the plan if it hits friction — reaching near-Carbon task success rates on Terminal-Bench 4.0 while consuming 24% less quota and completing 19% faster on average.
Context
Splitting one coding task between a frontier planner and a fast executor model could cut cost and time for agent work without giving up much accuracy.
Antigravity is Google's agent coding environment. On November 12 Google also launched Gemini 4 Hydrogen, a fast model in the Gemini 4 family, alongside the larger Gemini 4 Carbon. Orchestrator lets one session use both models instead of sending a whole task to a single model.
Deep dive
Google posted on November 12 that it is rolling out Orchestrator in Antigravity to Google AI Ultra subscribers. The feature lets a user run multiple models in a single session instead of routing the entire task to one model.
According to Google, Orchestrator pairs a frontier model with a fast execution model. Gemini 4 Carbon sets the plan, hands off code edits and testing to Gemini 4 Hydrogen, and steps back in to repair the plan if the work hits friction.
Google says this setup reaches near Carbon task success rates on Terminal Bench 4.0 while consuming 24% less quota and finishing 19% faster on average. Those figures come from Google and were not independently checked in the posts scanned.
The rollout came on the same day Google introduced Gemini 4 Hydrogen, which it describes as an extremely capable and fast model meant to bring Gemini 4 to everyone. The post included a video of the Antigravity interface with Gemini 4 Carbon selected in the model picker. Orchestrator is limited to the AI Ultra tier for now.
What to expect next
Watch whether Google brings Orchestrator to lower paid tiers or to the Gemini API, and whether outside developers confirm the quota and speed savings on their own projects. Other agent coding tools may adopt similar planner and executor splits between a large model and a fast one. Benchmarks that compare orchestrated runs with single model runs on the same tasks would show how much accuracy, if any, is lost.