According to @GeminiApp, Gemini 3 introduces a 'Deep Think' mode designed for Ultra users seeking advanced AI reasoning capabilities. Users can activate this feature by selecting ‘Deep Think’ in the prompt bar, choosing ‘Thinking’ from the model drop-down, and then submitting their prompt. This mode is optimized for complex problem-solving and in-depth analysis, offering businesses and developers enhanced precision for tasks such as strategic planning, research synthesis, and high-stakes decision-making. The rollout of Deep Think mode signals a market shift towards more specialized AI tools tailored for professional and enterprise applications (source: GeminiApp on Twitter, December 4, 2025).