Benchmark Almanac

tau-bench Airline

Not in model cards

Agents help simulated airline customers through tools while following airline policies on the original tasks. The score is pass^1 as a percentage.

One track of tau-bench. The tau-bench record keeps lab scores that combine tracks. Authors mark these original tasks as outdated and point to later benchmarks with revised tasks.

Made by
Sierra
Released
June 2024
Kind
Customer service
Level
Everyday
Scored
Checked automatically
Answers
Agent task
Tasks
All public
Strongest model tested
Claude 3.5 Sonnet (October 2024) #149 on the capability index
Last model added
October 2024
Scores refreshed
November 12th, 2026

In the authors’ words

Existing benchmarks do not test language agents on their interaction with human users or ability to follow domain-specific rules, both of which are vital for deploying them in real world applications. We propose τ-bench, a benchmark emulating dynamic conversations between a user (simulated by language models) and a language agent provided with domain-specific API tools and policy guidelines. We employ an efficient and faithful evaluation process that compares the database state at the end of a conversation with the annotated goal state. We also propose a new metric (pass^k) to evaluate the reliability of agent behavior over multiple trials. Our experiments show that even state-of-the-art function calling agents (like gpt-4o) succeed on <50% of the tasks, and are quite inconsistent (pass^8 <25% in retail). Our findings point to the need for methods that can improve the ability of agents to act consistently and follow rules reliably.

Abstract of τ-bench: A Benchmark for Tool-Agent-User Interaction in Real-World Domains (arXiv:2406.12045, CC0)
4
Entries on its own leaderboard, 2 models we track

Claude 3.5 Sonnet (October 2024) leads with 46%

Best score per entry from the benchmark's own leaderboard, read on November 12th, 2026. Where a model ran with several settings or harnesses, we keep its best. Names in gray aren't in our model list: fine-tunes, agent systems, products and older models. They don't count toward leaders.

  1. 1 Claude 3.5 Sonnet (October 2024) 46%
  2. 2 gpt-4o (snapshot unspecified) 42%
  3. 3 Claude 3.5 Sonnet 36%
  4. 4 gpt-4o-mini (snapshot unspecified) 22.5%

Source: Official tau-bench Airline leaderboard

#EntryScoreSettingDateSource
1 Claude 3.5 Sonnet (October 2024) 46% tool-calling Oct 2024 Official leaderboard
2 gpt-4o (snapshot unspecified) 42% tool-calling Official leaderboard
3 Claude 3.5 Sonnet 36% tool-calling Jun 2024 Official leaderboard
4 gpt-4o-mini (snapshot unspecified) 22.5% tool-calling Official leaderboard

Scores over time

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 Best so far
0% 20% 40% 60% 80% 100% 2024 2025 Near the ceiling (85%) Claude 3.5 Sonnet (October 2024) Claude 3.5 Sonnet 0% 20% 40% 60% 80% 100% 2024 2025 Near the ceiling (85%) Claude 3.5 Sonnet (October 2024) Claude 3.5 Sonnet

Source: Official tau-bench Airline leaderboard

No lab model card reports it yet

We read the headline results of 522 launch posts from 52 labs, and none of them list this benchmark.

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%