Better Call CLAUSE: A Discrepancy Benchmark for Auditing LLMs Legal Reasoning Capabilities
Manan Roy Choudhury, Adithya Chandramouli, Mannan Anand, Vivek Gupta
Abstract
The rapid integration of large language models (LLMs) into high-stakes legal work has exposed a critical gap: no benchmark exists to systematically stress-test their reliability against the nuanced, adversarial, and often subtle flaws present in real-world contracts. To address this, we introduce CLAUSE, a first-of-its-kind benchmark designed to evaluate the fragility of an LLM’s legal reasoning. We study the capabilities of LLMs to detect and reason about fine-grained discrepancies by producing over 7500 real-world perturbed contracts from foundational datasets like CUAD and ContractNLI. Our novel, persona-driven pipeline generates 10 distinct anomaly categories, which are then validated against official statutes using a Retrieval-Augmented Generation (RAG) system to ensure legal fidelity. We use CLAUSE to evaluate leading LLMs’ ability to detect embedded legal flaws and explain their significance. Our analysis shows a key weakness: these models often miss subtle errors and struggle even more to justify them legally. Our work outlines a path to identify and correct such reasoning failures in legal AI.- Anthology ID:
- 2026.findings-eacl.305
- Volume:
- Findings of the Association for Computational Linguistics: EACL 2026
- Month:
- March
- Year:
- 2026
- Address:
- Rabat, Morocco
- Editors:
- Vera Demberg, Kentaro Inui, Lluís Marquez
- Venue:
- Findings
- SIG:
- Publisher:
- Association for Computational Linguistics
- Note:
- Pages:
- 5776–5818
- Language:
- URL:
- https://preview.aclanthology.org/ingest-eacl/2026.findings-eacl.305/
- DOI:
- Cite (ACL):
- Manan Roy Choudhury, Adithya Chandramouli, Mannan Anand, and Vivek Gupta. 2026. Better Call CLAUSE: A Discrepancy Benchmark for Auditing LLMs Legal Reasoning Capabilities. In Findings of the Association for Computational Linguistics: EACL 2026, pages 5776–5818, Rabat, Morocco. Association for Computational Linguistics.
- Cite (Informal):
- Better Call CLAUSE: A Discrepancy Benchmark for Auditing LLMs Legal Reasoning Capabilities (Choudhury et al., Findings 2026)
- PDF:
- https://preview.aclanthology.org/ingest-eacl/2026.findings-eacl.305.pdf