Google ships Gemini 3 Deep Think to Ultra: 41.0% on Humanity's Last Exam
On 4 December Google rolled Gemini 3 Deep Think out to Google AI Ultra subscribers in the Gemini app, the reasoning mode it previewed when Gemini 3 Pro launched on 18 November. Google reports 41.0% on Humanity's Last Exam without tools and 45.1% on ARC-AGI-2 with code execution, attributing the jump to advanced parallel reasoning that explores multiple hypotheses simultaneously. Answers typically take minutes, and the mode is gated behind the $250/month Ultra tier.
The timing is pointed: this landed two days after Altman's code-red memo, marking the second Google release in three weeks to set the benchmark bar OpenAI is now spending a surge to match. It is also routed to consumers first — a toggle in the Gemini app — rather than to a documented API tier, so it is a demonstration of frontier reasoning capability more than a buildable endpoint.

WHY IT MATTERS
The benchmark race is less interesting than the gating: when the top reasoning tier ships subscription-only, the buildable surface stays a generation behind at token prices. Plan your evaluation harness so swapping in a stronger model is a config change, and check whether your hardest tasks genuinely need frontier reasoning before assuming the next benchmark leader is the correct default for your traffic.
