Two new Google models — Gemini 3.5 Flash and Gemini 3.5 Flash (Extended Reasoning) — are now available in Threads. Both models are fast and well-suited to content generation, drafting, and research tasks, giving you more choice when deciding which AI best fits your current project.
New — Gemini 3.5 Flash and Gemini 3.5 Flash (Extended Reasoning) are now available in the model selector inside Threads.
How to use it
Open an existing Thread or start a new one using the New Thread button.
Click the model dropdown at the top of the message composer.
Select Gemini 3.5 Flash for quick, responsive replies, or Gemini 3.5 Flash (Extended Reasoning) when you want the model to work through a problem more carefully before responding.
Type your message as normal. Your chosen model will be applied immediately.
What is extended reasoning mode in Gemini 3.5 Flash?
Gemini 3.5 Flash (Extended Reasoning) uses an extended reasoning mode, meaning the model takes additional steps to think through complex requests before giving you an answer. This can be useful for tasks like analysing a creative brief, planning a multi-channel campaign structure, or working through a nuanced brand challenge. Responses may take slightly longer than the standard Flash model, but the extra reasoning typically produces more considered output.
How should you choose between Gemini 3.5 Flash and Extended Reasoning?
If you just need a quick first draft or a fast answer, Gemini 3.5 Flash is a good default — it responds quickly and works well with your Brand Hub context.
Switch to Gemini 3.5 Flash (Extended Reasoning) when the task benefits from deeper analysis, such as reviewing a strategy document or generating a structured content plan.
Like all models in Threads, both Gemini 3.5 Flash variants automatically inherit your Brand Hub context — your voice guidelines, guardrails, and brand files apply without any extra setup.