Cached at:
07/30/26, 06:26 PM
# SpaceXAI launches Grok Voice Think Fast 2.0 on Agent Builder
Source: [https://www.testingcatalog.com/spacexai-launches-grok-voice-think-fast-2-0-on-agent-builder/](https://www.testingcatalog.com/spacexai-launches-grok-voice-think-fast-2-0-on-agent-builder/)
xAI has introduced Grok Voice Think Fast 2\.0, its next\-generation speech\-to\-speech model, with gains in intelligence, transcription accuracy, conversational behavior, and tool use\. The model is aimed at developers[building voice agents](https://www.testingcatalog.com/icymi-xai-debuts-grok-voice-agent-builder-for-enterprises/)and costs $0\.08 per minute of audio\. xAI expects it to raise performance across almost all use cases without changes to existing prompts\.
On Artificial Analysis’ speech\-to\-speech benchmark, Think Fast 2\.0 scored 82\.9% overall, up from 75\.7% for version 1\.0 and ahead of GPT\-Realtime\-2\.1 at 79\.1% and Gemini 3\.1 Flash at 69\.5%\. Its agentic score reached 56\.5%, compared with 52\.1% for its predecessor, 45\.7% for GPT\-Realtime\-2\.1, and 37\.7% for Gemini 3\.1 Flash\. Time to first audio fell from 1\.25 seconds to 0\.70 seconds\. The model’s 95\.1% conversational benchmark score was just below GPT\-Realtime\-2\.1 at 95\.7%\.
> Announcing Grok Voice Think Fast 2\.0, our next\-generation voice model with improved intelligence, transcription accuracy, and conversational capabilities\.[https://t\.co/XUiX1CouKz](https://t.co/XUiX1CouKz?ref=testingcatalog.com)[pic\.twitter\.com/Nel3zwzkwY](https://t.co/Nel3zwzkwY?ref=testingcatalog.com) — SpaceXAI \(@SpaceXAI\)[July 29, 2026](https://x.com/SpaceXAI/status/2082529280341553209?ref_src=twsrc%5Etfw&ref=testingcatalog.com)
Transcription is another major focus\. In xAI’s evaluation of thousands of short phrases across 24 languages, the company reported accuracy improvements of 1\.5 to 2\.0 times versus Deepgram Nova 3 and ElevenLabs Scribe v2, and 1\.4 times versus Think Fast 1\.0\. xAI says the gap is roughly 10× under substantial background noise and telephony compression\. The comparison uses the word error rate, with lower scores preferred\.
Think Fast 2\.0 reasons in parallel with speech, a design intended to preserve latency while handling more complex queries\. Median relative reasoning\-token use fell to 0\.4 times, using the predecessor’s 1\.0 times as a baseline\. xAI says this lets production tool calls usually execute before the agent finishes its first sentence\. Reinforcement learning also pushed the model toward shorter sentences, one question at a time, and less fluff while guiding users through complex workflows\.
For[SpaceXAI](https://www.testingcatalog.com/tag/grok/), this release is a push to make Grok Voice more dependable in real customer workflows\. An A/B test on Starlink’s phone service produced higher sales conversion and support containment rates, according to the company\. On August 5, 2026, the grok\-voice\-latest alias will automatically move from grok\-voice\-think\-fast\-1\.0 to grok\-voice\-think\-fast\-2\.0\. Developers who want the prior model must pin the 1\.0 identifier before the switch; everyone else needs to take no action\.
[Source](https://x.ai/news/grok-voice-think-fast-2?ref=testingcatalog.com)