Zero, the voice assistant in Model Explorer at 0xr.space, works with no key and no sign-in while Model Explorer launches: press Zero on the dock and speak. Settings says “Free while Model Explorer launches. Add your own key later.” Once you add your own Gemini API key, Zero runs on your key and the preview's limits no longer apply.
The preview is issued in sessions of 10 minutes, with a daily allowance for each device and network and a shared total for everyone, reset at midnight UTC. When it is spent the panel says “The preview allowance resets daily. Add your own Gemini API key in Settings to keep going now.” A key you add is kept only in this browser.
No. The preview needs nothing, and a key of your own is pasted into Settings, not into an account.
Only in this browser on this device. Add it again on each device you use.
Every day at midnight UTC.
That depends on your Google AI Studio plan; Google sets the free tier and its limits, not Zero.