Verdict Without the Rule: Diagnosing and Auditing Regulatory Rule Sensitivity in LLM Compliance Systems

Saisab Sadhu, Aadit Sengupta, Vinay kumar Sankarapu, Pratinav Seth


Abstract
Large language model compliance systems are deployed on the assumption that a verdict depends on the regulatory rule it is given. We test this directly across five models and 20 regulatory and platform-policy domains: delete, swap, or negate the governing rule while holding the case fixed, and check whether the verdict changes (OCS) or the model’s internal representation of compliance shifts at all (ICS-delta). Neither moves much: models’ verdicts are often invariant to substantial perturbations of the supplied rule, and the guard model, evaluated here under a custom-rule adaptation of its native taxonomy, is the least rule-sensitive and least accurate of the five, barely above chance (51%, versus 90–92% for general-purpose models). This reflects easy cases more than blanket neglect: on cases where deleting the rule changes a previously correct model prediction, models do track it closely. Neither better prompting nor direct intervention on the model’s internal representations closes this gap. Accuracy alone does not establish that a compliance verdict is grounded in the supplied rule.
Anthology ID:
2026.nllp-1.12
Volume:
Proceedings of the Natural Legal Language Processing Workshop 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Nikolaos Aletras, Ilias Chalkidis, Leslie Barrett, Cătălina Goanță, Daniel Preoțiuc-Pietro, Gerasimos Spanakis, Shanshan Xu
Venues:
NLLP | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
119–132
Language:
URL:
https://aclanthology.org/2026.nllp-1.12/
DOI:
Bibkey:
Cite (ACL):
Saisab Sadhu, Aadit Sengupta, Vinay kumar Sankarapu, and Pratinav Seth. 2026. Verdict Without the Rule: Diagnosing and Auditing Regulatory Rule Sensitivity in LLM Compliance Systems. In Proceedings of the Natural Legal Language Processing Workshop 2026, pages 119–132, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Verdict Without the Rule: Diagnosing and Auditing Regulatory Rule Sensitivity in LLM Compliance Systems (Sadhu et al., NLLP 2026)
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PDF:
https://aclanthology.org/2026.nllp-1.12.pdf