@inproceedings{liu-etal-2026-adaptiveguard,
title = "{A}daptive{G}uard: Treating Constraints as Falsifiable Hypotheses for {LLM} Agents in Dynamic Interactive Environments",
author = "Liu, Pengxiang and
Ren, Tao and
Xiong, Wei and
Li, Lijie and
Wang, Junjie and
Hu, Jun",
editor = "Lee, Hung-Yi and
Dev, Sunipa and
Li, Jessy and
Elliott, Desmond",
booktitle = "Findings of the {A}ssociation for {C}omputational {L}inguistics: {EMNLP} 2026",
month = oct,
year = "2026",
address = "Budapest, Hungary",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.findings-emnlp.1193/",
pages = "25186--25205",
ISBN = "979-8-89176-462-0",
abstract = "Large Language Models (LLMs) have shown impressive reasoning capabilities in agents for complex interactive environments. However, these agents frequently propose actions that violate physical or procedural constraints. Recent neuro-symbolic guards mitigate such errors by compiling explicit admissibility rules from oracle demonstrations, yet treat them as fixed laws{---}a closed-world assumption that breaks down under sparse demonstrations or environment shift, leaving either missing rules that fail to block unsafe actions or stale rules that wrongly reject valid alternatives. To address this, we introduce **AdaptiveGuard** ([code](https://github.com/lpxwork666111/AdaptiveGuard)), an Adaptive framework that Guards LLM agents by treating constraints as *falsifiable hypotheses*. Each rule is represented by a Beta-distributed validity belief mapped to *tentative*, *confirmed*, and *deprecated* tiers; uncertain rule blockers are then challenged through a zero-extra-call falsification gate; and these rule beliefs are continuously updated via contrastive feedback attribution from environment evidence. Benchmark experiments on ScienceWorld and VirtualHome show aggregate gains over strong static constraint guards, especially in novel scenarios. Complementary post-hoc diagnostics under sparse supervision and controlled shift show improved adaptation, while observed failed-trial runs remain below the configured budget cap and the conservative-bias proxy declines over the measured horizon."
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<abstract>Large Language Models (LLMs) have shown impressive reasoning capabilities in agents for complex interactive environments. However, these agents frequently propose actions that violate physical or procedural constraints. Recent neuro-symbolic guards mitigate such errors by compiling explicit admissibility rules from oracle demonstrations, yet treat them as fixed laws—a closed-world assumption that breaks down under sparse demonstrations or environment shift, leaving either missing rules that fail to block unsafe actions or stale rules that wrongly reject valid alternatives. To address this, we introduce **AdaptiveGuard** ([code](https://github.com/lpxwork666111/AdaptiveGuard)), an Adaptive framework that Guards LLM agents by treating constraints as *falsifiable hypotheses*. Each rule is represented by a Beta-distributed validity belief mapped to *tentative*, *confirmed*, and *deprecated* tiers; uncertain rule blockers are then challenged through a zero-extra-call falsification gate; and these rule beliefs are continuously updated via contrastive feedback attribution from environment evidence. Benchmark experiments on ScienceWorld and VirtualHome show aggregate gains over strong static constraint guards, especially in novel scenarios. Complementary post-hoc diagnostics under sparse supervision and controlled shift show improved adaptation, while observed failed-trial runs remain below the configured budget cap and the conservative-bias proxy declines over the measured horizon.</abstract>
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%0 Conference Proceedings
%T AdaptiveGuard: Treating Constraints as Falsifiable Hypotheses for LLM Agents in Dynamic Interactive Environments
%A Liu, Pengxiang
%A Ren, Tao
%A Xiong, Wei
%A Li, Lijie
%A Wang, Junjie
%A Hu, Jun
%Y Lee, Hung-Yi
%Y Dev, Sunipa
%Y Li, Jessy
%Y Elliott, Desmond
%S Findings of the Association for Computational Linguistics: EMNLP 2026
%D 2026
%8 October
%I Association for Computational Linguistics
%C Budapest, Hungary
%@ 979-8-89176-462-0
%F liu-etal-2026-adaptiveguard
%X Large Language Models (LLMs) have shown impressive reasoning capabilities in agents for complex interactive environments. However, these agents frequently propose actions that violate physical or procedural constraints. Recent neuro-symbolic guards mitigate such errors by compiling explicit admissibility rules from oracle demonstrations, yet treat them as fixed laws—a closed-world assumption that breaks down under sparse demonstrations or environment shift, leaving either missing rules that fail to block unsafe actions or stale rules that wrongly reject valid alternatives. To address this, we introduce **AdaptiveGuard** ([code](https://github.com/lpxwork666111/AdaptiveGuard)), an Adaptive framework that Guards LLM agents by treating constraints as *falsifiable hypotheses*. Each rule is represented by a Beta-distributed validity belief mapped to *tentative*, *confirmed*, and *deprecated* tiers; uncertain rule blockers are then challenged through a zero-extra-call falsification gate; and these rule beliefs are continuously updated via contrastive feedback attribution from environment evidence. Benchmark experiments on ScienceWorld and VirtualHome show aggregate gains over strong static constraint guards, especially in novel scenarios. Complementary post-hoc diagnostics under sparse supervision and controlled shift show improved adaptation, while observed failed-trial runs remain below the configured budget cap and the conservative-bias proxy declines over the measured horizon.
%U https://aclanthology.org/2026.findings-emnlp.1193/
%P 25186-25205
Markdown (Informal)
[AdaptiveGuard: Treating Constraints as Falsifiable Hypotheses for LLM Agents in Dynamic Interactive Environments](https://aclanthology.org/2026.findings-emnlp.1193/) (Liu et al., Findings 2026)
ACL