Benchmark Almanac

tau3-bench

Mercury 2.5 96% leads since September 2026
Qwen3.5 397B-A17B 87.9% leads since March 2026
Mercury 2.5 96% leads since September 2026
In use

Agents use tools and follow policies while talking with simulated users in airline, retail, telecom, and banking domains. Scoring is task success rate.

Release 1.0.1 in July 2026 fixed banking grading, so earlier banking scores do not compare, and τ-bench 2.0 followed in October 2026.

Made by
Sierra
Released
March 2026
Kind
Customer service
Level
Everyday
Scored
Checked automatically
Answers
Agent task
Tasks
All public
Strongest model tested
Kimi K3 #24 on the capability index
Last in a launch post
October 2026
Last model added
October 2026
Scores refreshed
November 12th, 2026

In the authors’ words

Conversational agents are increasingly deployed in knowledge-intensive settings, where correct behavior depends on retrieving and applying domain-specific knowledge from large, proprietary, and unstructured corpora during live interactions with users. Yet most existing benchmarks evaluate retrieval or tool use independently of each other, creating a gap in realistic, fully agentic evaluation over unstructured data in long-horizon interactions. We introduce τ-Knowledge, an extension of τ-Bench for evaluating agents in environments where success depends on coordinating external, natural-language knowledge with tool outputs to produce verifiable, policy-compliant state changes. Our new domain, τ-Banking, models realistic fintech customer support workflows in which agents must navigate roughly 700 interconnected knowledge documents while executing tool-mediated account updates. Across embedding-based retrieval and terminal-based search, even frontier models with high reasoning budgets achieve only ~25.5% pass^1, with reliability degrading sharply over repeated trials. Agents struggle to retrieve the correct documents from densely interlinked knowledge bases and to reason accurately over complex internal policies. Overall, τ-Knowledge provides a realistic testbed for developing agents that integrate unstructured knowledge in human-facing deployments.

Abstract of τ-Knowledge: Evaluating Conversational Agents over Unstructured Knowledge (arXiv:2603.04370, CC0)
14
Models scored in lab cards
14
Launch posts list it, from 13 labs
1
System card reports it, from 1 lab

Mercury 2.5 leads with 96%

Best score per model as labs report them in their own cards. Labs pick their own settings, so these compare less cleanly than independent runs.

Qwen3.5 397B-A17B leads with 87.9% across all independent runs

Best score per model across the official leaderboard, Epoch AI’s own runs and any board Epoch AI copied. Each bar and row names its source.

Mercury 2.5 leads with 96%, claims included

Best score per model from every source, including labs’ own numbers and claims Epoch AI collected from reports and papers. Labs pick their own settings, so a claim can beat an independent run of the same model.

  1. 1 Mercury 2.5 96%
  2. 2 Nemotron 3 Ultra 86.9%
  3. 3 GPT-Live-1 86.2%
  4. 4 MiMo-V2.5-Pro 72.9%
  5. 5 Qwen 3.6 Plus 70.7%
  6. 6 GLM-5.1 70.6%
  7. 7 LFM3-1.7B 68%
  8. 8 ERNIE 5.1 67.9%
  9. 9 Qwen 3.6 35B-A3B 67.2%
  10. 10 Mistral Medium 3.5 63.2%
  11. 11 Granite 4.2 30B 62%
  12. 12 Spark-X2.6-4B 34.7%
  13. 13 Kimi K3 33.4%
  14. 14 Grok 4.5 32.6%

Source: Labs’ model cards

#ModelScoreSettingDateSource
1 Mercury 2.5 96% Sep 2026 Lab model card
2 Nemotron 3 Ultra 86.9% Jun 2026 Lab model card
3 GPT-Live-1 86.2% Jul 2026 Lab model card
4 MiMo-V2.5-Pro 72.9% Apr 2026 Lab model card
5 Qwen 3.6 Plus 70.7% Apr 2026 Lab model card
6 GLM-5.1 70.6% Apr 2026 Lab model card
7 LFM3-1.7B 68% Oct 2026 Lab model card
8 ERNIE 5.1 67.9% May 2026 Lab model card
9 Qwen 3.6 35B-A3B 67.2% Apr 2026 Lab model card
10 Mistral Medium 3.5 63.2% May 2026 Lab model card
11 Granite 4.2 30B 62% Aug 2026 Lab model card
12 Spark-X2.6-4B 34.7% Oct 2026 Lab model card
13 Kimi K3 33.4% Jul 2026 Lab model card
14 Grok 4.5 32.6% Jul 2026 Lab model card
#ModelScoreSettingDateSource
1 Qwen3.5 397B-A17B 87.9% enabled Feb 2026 Official leaderboard
2 Claude Opus 4.5 85.3% high Nov 2025 Official leaderboard
3 GPT-5.2 84.8% high Dec 2025 Official leaderboard
4 Gemini 3 Flash 83.5% high Dec 2025 Official leaderboard
5 Gemini 3 Pro 82.5% high Nov 2025 Official leaderboard
6 GLM-5 81% enabled Feb 2026 Official leaderboard
7 Claude Sonnet 4.5 76.4% enabled Sep 2025 Official leaderboard
#ModelScoreSettingDateSource
1 Mercury 2.5 96% Sep 2026 Lab model card
2 Qwen3.5 397B-A17B 87.9% enabled Feb 2026 Official leaderboard
3 Nemotron 3 Ultra 86.9% Jun 2026 Lab model card
4 GPT-Live-1 86.2% Jul 2026 Lab model card
5 Claude Opus 4.5 85.3% high Nov 2025 Official leaderboard
6 GPT-5.2 84.8% high Dec 2025 Official leaderboard
7 Gemini 3 Flash 83.5% high Dec 2025 Official leaderboard
8 Gemini 3 Pro 82.5% high Nov 2025 Official leaderboard
9 GLM-5 81% enabled Feb 2026 Official leaderboard
10 Claude Sonnet 4.5 76.4% enabled Sep 2025 Official leaderboard
11 MiMo-V2.5-Pro 72.9% Apr 2026 Lab model card
12 Qwen 3.6 Plus 70.7% Apr 2026 Lab model card
13 GLM-5.1 70.6% Apr 2026 Lab model card
14 LFM3-1.7B 68% Oct 2026 Lab model card
15 ERNIE 5.1 67.9% May 2026 Lab model card
16 Qwen 3.6 35B-A3B 67.2% Apr 2026 Lab model card
17 Mistral Medium 3.5 63.2% May 2026 Lab model card
18 Granite 4.2 30B 62% Aug 2026 Lab model card
19 Spark-X2.6-4B 34.7% Oct 2026 Lab model card
20 Kimi K3 33.4% Jul 2026 Lab model card
21 Grok 4.5 32.6% Jul 2026 Lab model card

The benchmark's own leaderboard has 7 models. Switch the scores above to rank them together.

4 models have held number one in labs’ own numbers since its release in March 2026 Number one over time 2 models have held number one with claims included since its release in March 2026

Lab claims count from the day the card came out, independent runs from the model’s release. We draw one row each for the benchmark’s own leaderboard and what labs claim in their cards.

Qwen Xiaomi Corp NVIDIA Inception Labs
Own leaderboard Passed 85% in Mar 2026, by Qwen3.5 397B-A17B
Lab claims Passed 85% in Jun 2026, by Nemotron 3 Ultra

Sources: Official tau3-bench leaderboard and labs’ model cards

Claude Opus 4.5 on the official leaderboard passed 85% in November 2025

All the scores we have, one dot each, so a model tested at several settings appears more than once.

On the benchmark’s own leaderboard Reported by the lab in its model card Best so far
0% 20% 40% 60% 80% 100% 2026 2027 Near the ceiling (85%) Mercury 2.5 Qwen3.5 397B-A17B Gemini 3 Pro Claude Sonnet 4.5 0% 20% 40% 60% 80% 100% 2026 2027 Near the ceiling (85%) Mercury 2.5 Qwen3.5 397B-A17B

Sources: Official tau3-bench leaderboard and labs’ model cards

8 labs put it in a launch post in the last six months

Launch posts from every lab that has listed it, one tick per post. Tall colored ticks include it, and short gray ones leave it out.

Qwen
Z.ai
Xiaomi Corp
Baidu
Mistral AI
NVIDIA
OpenAI
xAI
Moonshot AI
IBM
Inception Labs
iFlytek
Liquid AI
DateLaunch postScoreAs the post writes it
Oct 27, 2026 LFM3-1.7B 68 τ³-bench
Oct 22, 2026 Spark-X2.6-4B 34.7 τ³-bench
Sep 8, 2026 Mercury 2.5 96 Tau3Bench Telecom (telecom domain only)
Aug 25, 2026 Granite 4.2 30B 62 τ³-bench (AVG)
Jul 16, 2026 Kimi K3 33.4 τ³-Banking
Jul 16, 2026 Grok 4.5 32.6 τ³-bench, banking, 32.6%
Jul 8, 2026 GPT-Live-1 86.2 Tau3 (Voice) Intelligence, Pass@1, GPT-Live-1 paired with GPT-6 Astra at medium reasoning effort (asterisked in the chart)
Jun 4, 2026 Nemotron 3 Ultra 86.9 Mean of TauBench V3 Airline 81.5 / Retail 86.4 / Telecom 92.9
May 22, 2026 Mistral Medium 3.5 63.2 Mean of τ³ Telecom / τ³ Airline / τ³ Retail / τ³ Banking
May 9, 2026 ERNIE 5.1 67.9 τ3-bench (avg@4)
Apr 27, 2026 MiMo-V2.5-Pro 72.9 τ³-bench
Apr 15, 2026 Qwen 3.6 35B-A3B 67.2 TAU3-Bench (gpt-5.2 user model)
Apr 7, 2026 GLM-5.1 70.6 τ³-Bench
Apr 2, 2026 Qwen 3.6 Plus 70.7 TAU3-Bench

One system card reports it

Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.

DateDocumentScoreAs the document writes itSection
Jun 9, 2026 Nemotron 3 Ultra technical report 70.9 TauBench V3 Average of Airline 81.5, Retail 86.4, Telecom 92.9, Banking 22.6 (Table 10) Capabilities

Versions

We switch the top row to each new version when it comes out. Open it for one row per version. An old version stays in play while people still test it, so whoever first takes it past 85% gets credit for closing it out.

Anthropic OpenAI Moonshot AI MiniMax Qwen Xiaomi Corp NVIDIA Inception Labs xAI
τ-bench 2.0 18 leaders
GPT-Live-1 79.9%
tau-bench Replaced by tau2-bench, Sep 2025
tau2-bench Passed 85% in Oct 2025, by MiniMax-M2
GPT-5.4 98.9%
tau3-bench Passed 85% in Jun 2026, by Nemotron 3 Ultra
τ-bench 2.0 2 leaders
GPT-Live-1 79.9%

Sources: Official leaderboards and labs’ model cards

More in Tool use

All 144 in Tool use
  • AutomationBench In use Agent completes end-to-end business workflows inside a simulated company exposing dozens of REST APIs. Graded on resulting state. Gemini 4 Carbon 53.9%
  • MCP Atlas In use Multi-step workflows over real MCP servers. Scores tool-use competency on realistic tasks. Gemini 4 Argon 90.7%
  • BFCL V4 In use Models call functions and tools, including multi-turn agentic tasks with web search and memory. Checked against expected calls and outcomes. Qwen3.7-Max 75%
  • τ³-bench Banking In use Agents act as banking customer-service reps over many turns with a simulated user, following policy. Pass^1 on the final database state. Qwen 3.8 Max 55.1%
  • Toolathlon-Verified In use 108 long-horizon tasks across 32 apps through about 600 MCP tools. Execution-based checkers inspect final environment state. GLM-5.3-Flash 78.4%
  • DeepSearchQA In use Questions that need multi-step search and synthesis. Final answers graded against references. Kimi K3 95%