Auto selects a Gemini model for each prompt. Google describes it as sending everyday questions to models intended for fast responses and using more advanced models when a task requires deeper reasoning. Users can inspect the model used beneath a response through More: “Show thinking steps” on the web or “See response details” on mobile.
Unsubscribed users can turn off Smart model selection in Settings > Usage limits. Google says doing so leaves Flash-Lite as their only chat model. Direct selection of a specific model in the picker is now part of Google AI subscription plans.
The announcement does not specify which models Auto can select, request limits, country availability, subscription prices, or the criteria used to route a prompt.