The Gemini Live API enables real-time, bidirectional voice conversations with Gemini models.
Standard voice models work well for immediate back-and-forth dialogue. You speak to the model, and it generates a spoken reply right away. But when a request requires planning, complex analysis, or external tools, direct responses hit a limit. The model must either answer without reasoning or pause silently while waiting for tools to finish.
Thinking in the Live API (gemini-3.8-live-extended-thinking) adds background
reasoning to real-time voice sessions. The model plans and calls asynchronous
tools in the background while speaking natural conversational fillers to keep
the interaction active.
This architecture changes the conversational lifecycle in two key ways:
- Conversational fillers: The model speaks intermediate updates (such as "Checking flight options now") while executing tools in the background.
- Interaction status tracking: Because the model can speak multiple times
during a single request, the server emits
interaction_status: "IN_PROGRESS"during background processing andinteraction_status: "IDLE"when the overall task completes.
The following diagram compares the interaction lifecycles between standard Live voice sessions and Thinking with background reasoning:
Choosing the right model
When deciding between gemini-3.8-live and gemini-3.8-live-extended-thinking,
weigh three main considerations: response latency, task complexity, and client
state handling.
When to use Gemini 3.8 Live
Use gemini-3.8-live for low-latency conversational voice agents where
immediate turn-taking is essential and tasks are direct.