τ³-bench#

Introduction#

τ³-bench (Tau Cubed Bench) is the v1.0.0 release of the tau-bench family. It builds on τ²-bench with a new knowledge-retrieval domain (banking_knowledge), 75+ task quality fixes across the existing domains, and an audio-native evaluation mode.

Project URL: https://github.com/sierra-research/tau2-bench (v1.0.0)
The PyPI package name is still tau2. τ³-bench cannot be installed in the same environment as τ²-bench (v0.2.0). Pick one.

Core Features:

Dynamic Interaction: Multi-turn user/agent simulation
Tool Integration: Agents must use the provided API tools correctly
Policy Adherence: Agents must follow domain policies
Knowledge Retrieval (new): RAG pipeline with BM25, dense embeddings (OpenAI / Qwen), grep, sandbox shell, and rerankers
Task Quality (new): 75+ corrected expected actions across airline / retail / banking

Supported Evaluation Domains:

airline: Airline customer service
retail: Retail customer service
telecom: Telecom customer service
banking_knowledge: Banking customer service backed by 698 policy/procedure documents (RAG)

Installation#

pip install evalscope
# Requires Python 3.12-3.13. Install tau3 with the [knowledge] extra so banking_knowledge works.
pip install "tau2[knowledge] @ git+https://github.com/sierra-research/tau2-bench@v1.0.0"

# Upstream v1.0.0 has eager voice imports even on the text-only path, so the
# following lightweight voice-related deps must be present (pyaudio needs
# `brew install portaudio` on macOS):
pip install pyaudio elevenlabs deepgram-sdk websockets jiwer pydub aiohttp scipy

Important

The dataset is automatically pulled from ModelScope (Dataset ID: evalscope/tau3-bench-data), and TAU2_DATA_DIR is configured for you.
Only supports evaluating the agent under test through OpenAI-compatible API services.
τ³-bench and τ²-bench cannot coexist (same package name tau2).

Usage#

Taking qwen-plus as an example. The official leaderboard typically uses user model = gpt-4.1-2025-04-14.

import os
from evalscope import TaskConfig, run_task

task_cfg = TaskConfig(
    model='qwen-plus',
    api_url='https://dashscope.aliyuncs.com/compatible-mode/v1',
    api_key=os.getenv('DASHSCOPE_API_KEY'),
    eval_type='openai_api',

    datasets=['tau3_bench'],
    dataset_args={
        'tau3_bench': {
            'subset_list': ['airline', 'retail', 'telecom', 'banking_knowledge'],
            'extra_params': {
                'user_model': 'qwen-plus',
                'api_key': os.getenv('DASHSCOPE_API_KEY'),
                'api_base': 'https://dashscope.aliyuncs.com/compatible-mode/v1',
                'generation_config': {
                    'temperature': 0.7,
                },
                # banking_knowledge only; other domains ignore these:
                'retrieval_config': 'bm25',
                'retrieval_config_kwargs': {},
            }
        }
    },

    eval_batch_size=5,
    limit=5,
    generation_config={'temperature': 0.6},
)

run_task(task_cfg)

Retrieval Configs (banking_knowledge)#

The retrieval_config extra param controls how the agent accesses the 698-document knowledge base. It is forwarded verbatim to tau2.run.run_task(retrieval_config=...).

Config	Tools given to agent	Extra requirements
`no_knowledge`	none	none (offline)
`full_kb`	none (whole KB stuffed into prompt)	none
`golden_retrieval`	none (gold-labeled docs in prompt)	none
`grep_only`	`grep`	none
`bm25` (default)	`KB_search` (BM25 sparse retrieval)	`rank-bm25` (in `[knowledge]` extra)
`openai_embeddings`	`KB_search` (dense, OpenAI)	`OPENAI_API_KEY`
`qwen_embeddings`	`KB_search` (dense, OpenRouter/Qwen)	`OPENROUTER_API_KEY`
`*_reranker`	adds LLM reranker	also `OPENAI_API_KEY`
`*_grep`	adds `grep` tool	inherits base config
`terminal_use` / `terminal_use_write`	sandboxed `shell`	npm `@anthropic-ai/sandbox-runtime` + ripgrep (and on Linux: bwrap, socat)
`alltools` / `alltools-qwen`	BM25 + dense + shell	combination of above

See the upstream README for the full matrix: https://github.com/sierra-research/tau2-bench/blob/v1.0.0/src/tau2/knowledge/README.md

Tips#

If using gpt-4.1 as the user simulator, set:
- extra_params.user_model='gpt-4.1-2025-04-14'
- extra_params.api_base='https://api.openai.com/v1'
- extra_params.api_key=<OPENAI_API_KEY>
For airline/retail/telecom-only runs, drop banking_knowledge from subset_list to avoid pulling in retrieval dependencies.

Evaluation Process#

Task initialization with domain tools and policies
User simulation generates natural requests
Agent under test produces tool-augmented responses
Multi-turn loop until completion or failure
Reward computed by tau3’s evaluator; mapped to acc in evalscope reports

Metric Description#

Pass^1: proportion of tasks completed on the first attempt (higher is better)
Aggregation: mean_and_pass_hat_k (supports repeats > 1 for pass@k)