Initial release of Gemini 3 Deep Think reasoning mode

## What changed Google released Gemini 3 Deep Think on December 4, 2025. Google AI Ultra subscribers received access to this reasoning mode inside the Gemini app. The mode runs iterative rounds of reasoning that test multiple hypotheses at once on math, science, and logic tasks.

Responses arrive after a few minutes rather than instantly. Users select Deep Think from the prompt bar and Thinking from the model dropdown to start a query.

## Why it matters Solo builders now have a dedicated path for problems that standard models still mishandle. This targets the exact pain points that appear in workflow automation, data mapping, and custom logic inside tools like Notion or Zapier.

The move pressures competitors who charge similar premiums for reasoning features. It also signals Google will keep advanced modes behind the highest tier rather than spreading them to lower plans.

## How to use it Open the Gemini app and confirm you hold a Google AI Ultra subscription. Choose Deep Think in the prompt bar, then pick Thinking in the model dropdown before submitting the task.

The system returns a notification once the response is ready. Start with one narrow, high-stakes problem such as debugging a multi-step automation script or verifying a data transformation rule.

## Watch for Track whether Deep Think produces fewer logic errors on real builder tasks over the next month. Watch for rate limits that make daily use impractical. Expect a follow-up release that adds direct export options into Notion databases or Zapier steps.