When2Tool (Multi-Hop): leaderboard

Multi-hop tool-use decisions from When2Tool (Sun et al., 2026): 450 test tasks in three simulated environments, each a chain of three dependent tool calls, at easy, medium and hard difficulty. Accuracy in percent of exact-form answers checked by a deterministic evaluator, with tools offered under a neutral default prompt, mean of three seeds; higher is better.

Metric: Accuracy (%; exact-form answers in a boxed final response, checked by a deterministic evaluator; simulated offline tool environments at easy, medium and hard difficulty; 450 multi-hop test tasks in 3 environments, each a chain of three dependent tool calls; tools offered under the neutral default prompt; mean of three seeds). Source: arxiv.org. Saturation forecast: Estimated already saturated. 6 models tracked.

Top models

#ModelScoreOverall rank
1Qwen 3 32B88.9#960
2Qwen 3 14B87.5#1235
3Qwen 3 4B 2507 Instruct82.1#2174
4Llama 3.3 70B Instruct62.4#1353
5Llama 3.1 8B40.2#4900
6Qwen 3 1.7B21.2#5551

No result here: #1 Claude Fable 5.2, #2 Gemini 4 Carbon, #5 Claude Opus 5.5.

Interactive version: theaggregate.ai/benchmark?slug=when2tool-multi-hop · How It Works · Data refreshed daily, snapshot 2026-11-12.