Role-Splitting

Google released Gemini 4 Hydrogen, a fast agentic model that edges out Gemini 4 Argon on the Artificial Analysis Intelligence Index (51 vs. 50) at a lower price. Its key design is role-splitting: in Google Antigravity, an Orchestrator mode has Gemini 4 Carbon plan while Hydrogen edits files, updates packages and runs tests, handing control back on friction. It scores 57% on Terminal-Bench 4.1 and finishes tasks 2.5x faster, though at $1.50/$7.50 per 1M tokens it costs twice the 3.8 Flash intro rate.