What exactly did arXiv 2604.13824 (v2) test and measure: environments, models, horizon, metrics, headline numbers, limits, and what is released?
arXiv 2604.13824 (Huang et al.; v1 submitted 2026-04-15 12:56:45 UTC, v2 2026-09-02 08:58:38 UTC, cs.LG, 20 pages) fine-tunes Word2World text world models (Qwen2.5-7B and Llama-3.1-8B bases) with GRPO using BehR, then tests them on WebShop and TextWorld with 200 held-out tasks per domain and four evaluation agents (Qwen3-8B, Qwen3-32B, GPT-4o, GPT-5). Trajectories average about ten steps (cap 50), so this is behaviour at short horizons, not long-horizon modelling. Headline: BehR beats its supervised starting point on CR_pw in 13 of 16 cells with 3 ties; the largest cell is WebShop Qwen3-8B 0.345 -> 0.483 (10/29 -> 14/29 tasks); single-step exact match is preserved or improved in three of four settings (lower for WebShop on the Llama base); WebShop lookahead success rises from 14.5% (ReAct) to 24.0% (W2W-WM) and 25.5% (BehR-WM) for Qwen3-8B. Each configuration was trained once and no seed variance is reported.
Structured fields
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"citations": [
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"url": "https://arxiv.org/abs/2604.13824v2",
"note": "candidate evidence excerpts"
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}Evidence claims
- [sourced_fact] arXiv 2604.13824 (Huang et al.; v1 submitted 2026-04-15 12:56:45 UTC, v2 2026-09-02 08:58:38 UTC, cs.LG, 20 pages) fine-tunes Word2World text world models (Qwen2.5-7B and Llama-3.1-8B bases) with GRPO using BehR, then tests them on WebShop and TextWorld with 200 held-out tasks per domain and four evaluation agents (Qwen3-8B, Qwen3-32B, GPT-4o, GPT-5). Trajectories average about ten steps (cap 50), so this is behaviour at short horizons, not long-horizon modelling. Headline: BehR beats its supervised starting point on CR_pw in 13 of 16 cells with 3 ties; the largest cell is WebShop Qwen3-8B 0.345 -> 0.483 (10/29 -> 14/29 tasks); single-step exact match is preserved or improved in three of four settings (lower for WebShop on the Llama base); WebShop lookahead success rises from 14.5% (ReAct) to 24.0% (W2W-WM) and 25.5% (BehR-WM) for Qwen3-8B. Each configuration was trained once and no seed variance is reported. · locator: candidate evidence excerpts source
Rights
| component | license | hosting | redistribution | modification | training | Evidence and notes |
|---|---|---|---|---|---|---|
| documentation | unknown | permitted | permitted | unknown | unknown | Applies to this original summary only, not to the cited sources. |