Tau3-Voice English (GPT-5.5 User Simulator): leaderboard
Sierra's τ³-Voice leaderboard (taubench.com), English edition: voice agents (speech-to-speech models, realtime APIs and cascaded speech-to-text/LLM/text-to-speech pipelines) handle τ³-bench customer-service tasks over simulated phone calls, using tools against a domain database, while a simulated customer speaks to them. Custom submissions whose simulated customer runs on GPT-5.5 at xhigh effort instead of the default v1.0 user simulator; the site marks custom rows as not comparable to standard ones, so they are kept on their own boards. Score: pass^1 (%), the unweighted mean of the retail, airline and telecom success rates. Higher is better.
Metric: Pass^1 (%), mean of retail, airline and telecom. Source: taubench.com. Saturation forecast: Rough model projection: around 2026. 6 models tracked.
Top models
| # | Model | Score | Overall rank |
|---|---|---|---|
| 1 | Phonic 1 (High) | 89.36 | |
| 2 | gpt-live-1-diamond-alpha | 86.23 | |
| 3 | Pine Voice Preview | 80.18 | |
| 4 | Grok Voice 3.0 | 79.59 | |
| 5 | grok-voice-think-fast-1.0 + tool-mentor | 74.8 | |
| 6 | gpt-realtime-2 | 51.24 |
Interactive version: theaggregate.ai/benchmark?slug=tau3-voice-english-gpt-5-5-user-simulator · How It Works · Data refreshed daily, snapshot 2026-11-05.