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xAI's Grok Voice Think Fast 1.0 leads the τ‑Voice agentic benchmark with a 52.1%…

Brief

Artificial Analysis' τ‑Voice benchmark extends τ²‑bench into speech-to-speech agent evaluation using an LLM-driven simulated customer and realistic audio (accents, noise, packet loss) across Airline (50), Retail (114) and Telecom (114) tasks. xAI's Grok Voice Think Fast 1.0 tops the ranking at 52.1% (5.6 min); OpenAI and Gemini models follow in the high‑30% range, and overall S2S still resolves roughly half of realistic customer-service scenarios.

Why it matters

xAI's Grok Voice Think Fast 1.0 leads the τ‑Voice agentic benchmark with a 52.1% task-success rate and averages 5.6 minutes per conversation (second-longest duration).

Key details

  • OpenAI's GPT‑Realtime‑2 (High) scored 39.8% (3.0 min) and GPT‑Realtime‑1.5 scored 38.8% (4.8 min); Google Gemini 3.1 Flash Live Preview - High scored 37.7% (3.8 min).
  • τ‑Voice (extending τ²‑bench) evaluates multi-turn S2S instruction-following and tool use with an LLM-driven simulated user and realistic audio (accents, background noise, packet loss) across Airline (50), Retail (114) and Telecom (114) scenarios; even top S2S models resolve only about half of end-to-end customer-service cases and performance varies by audio condition and conversation length.
Source evidence

Grok Voice is #1!

Artificial Analysis (@ArtificialAnlys)

Announcing agentic performance benchmarking for Speech to Speech models on Artificial Analysis. We use 𝜏-Voice to measure tool calling and customer interaction voice agent capabilities in realistic customer service scenarios

Even the strongest Speech to Speech (S2S) models today resolve only about half of realistic customer service scenarios end-to-end - a meaningful gap relative to frontier text-based agents on the same tasks. Voice channels introduce significant complexity: challenging accents, background noise, and packet loss, all while requiring fast responses, consistency across long multi-turn conversations, and reliable tool use. Performance also varies considerably by audio condition: in clean audio some models perform notably better, but realistic conditions continue to pose a challenge. Conversation duration also varies meaningfully across models, with implications for both customer experience and operational cost.

About 𝜏-Voice:
Our Agentic Performance benchmark is based on 𝜏-Voice (Ray, Dhandhania, Barres & Narasimhan, 2026), which extends 𝜏²-bench into the voice modality to evaluate S2S models on realistic customer service tasks. It measures multi-turn instruction following, support of a simulated customer through a complete interaction, and tool use against simulated customer service systems. The simulated user combines an LLM-driven decision model with realistic audio synthesis: diverse accents, background noise, and packet loss modelled on real network conditions.

This complements our Big Bench Audio benchmark measuring intelligence and Conversational Dynamics (Full Duplex Bench subset) benchmark measuring conversational naturalness. Scores are the average of three independent pass@1 trials. We evaluate under realistic audio conditions using the 𝜏²-bench base task split across three domains:
➤ Airline (50 scenarios): e.g., changing a flight, rebooking under policy constraints
➤ Retail (114 scenarios): e.g., disputing a charge, processing a return
➤ Telecom (114 scenarios): e.g., resolving a billing issue, troubleshooting a service problem

Task success is determined by deterministic checks against expected actions and final database state, consistent with the 𝜏²-bench evaluator.

Key results:
xAI's Grok Voice Think Fast 1.0 is the clear leader at 52.1%, averaging 5.6 minutes per conversation, the second-longest overall. OpenAI's GPT-Realtime-2 (High) (39.8%, 3.0 min) and GPT-Realtime-1.5 (38.8%, 4.8 min) follow, with Gemini 3.1 Flash Live Preview - High close behind at 37.7% (3.8 min).

Speech to Speech is a fast evolving modality and we expect movement in rankings as we continue to add new models with these capabilities, and model robustness improves.

Congratulations @xAI @elonmusk! See below for further detail ⬇️

— https://nitter.net/ArtificialAnlys/status/2054234919887573292#m