CAPSafe: A Benchmark for Contextual Action and Plan Safety Reasoning in Embodied Agents

Youmna Farag, Svetlana Stoyanchev, Simon Keizer, Mohan Li, Rama Doddipatla


Abstract
Reasoning about safety is essential for embodied agents powered by large language models (LLMs). We introduce the Contextual Action and Plan Safety benchmark (CAPSafe), designed to evaluate safety reasoning at two levels: (1) an action-level dataset that tests whether a single action is safe given its environmental context, and (2) a plan-level dataset that evaluates whether agents can generate safe long-horizon plans for complex hazardous household tasks. CAPSafe models safety conditions where hazards are situational (inferred from object properties), multiple hazards can co-occur within the same environment, and each is annotated with a relative severity level for fine-grained analysis. Evaluating nine closed and open-source LLMs reveals a substantial gap between hazard recognition and safe long-horizon planning. Several models achieve high accuracy in recognizing unsafe actions (exceeding 90% in the best cases), yet safe long-horizon planning remains substantially harder. Gemini-3-pro achieves the highest safe success rate (78.19%), while other models remain below 65%. These results highlight that robust safety reasoning over long action sequences remains an open challenge.
Anthology ID:
2026.realm-1.23
Volume:
Proceedings of the Second Workshop for REsearch on Agent Language Models (REALM 2026)
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Ehsan Kamalloo, Nicolas Gontier, Nikolai Rozanov, Maryam Hashemzadeh, Akhil Arora
Venues:
REALM | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
341–364
Language:
URL:
https://aclanthology.org/2026.realm-1.23/
DOI:
Bibkey:
Cite (ACL):
Youmna Farag, Svetlana Stoyanchev, Simon Keizer, Mohan Li, and Rama Doddipatla. 2026. CAPSafe: A Benchmark for Contextual Action and Plan Safety Reasoning in Embodied Agents. In Proceedings of the Second Workshop for REsearch on Agent Language Models (REALM 2026), pages 341–364, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
CAPSafe: A Benchmark for Contextual Action and Plan Safety Reasoning in Embodied Agents (Farag et al., REALM 2026)
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PDF:
https://aclanthology.org/2026.realm-1.23.pdf