Knowing but Not Doing: Discourse-level Constraints Adherence of Large Language Models

Zhonghua Hong, Sihang Jiang, Keyi Wang, Xiaojun Meng, Jiansheng Wei, Jiaqing Liang, Yanghua Xiao


Abstract
Instruction following in large language models (LLMs) is commonly evaluated at the sentence or surface level, leaving discourse-level constraints underexplored. We study discourse-level instruction following by formalizing it as a structured constraint adherence problem and constructing both explicit and implicit benchmarks for evaluation. Experiments are conducted across models of different scales, revealing a systematic recognition–adherence gap: models can identify discourse constraints but frequently fail to adhere to them during generation with specific failure modes. This failure stems from a fundamental misalignment between standard training objectives and global structural integrity. Importantly, models show substantially improved adherence when discourse-level structural objectives are explicitly optimized.
Anthology ID:
2026.findings-emnlp.1083
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
22934–22949
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1083/
DOI:
10.18653/2026.findings-emnlp.1083
Bibkey:
Cite (ACL):
Zhonghua Hong, Sihang Jiang, Keyi Wang, Xiaojun Meng, Jiansheng Wei, Jiaqing Liang, and Yanghua Xiao. 2026. Knowing but Not Doing: Discourse-level Constraints Adherence of Large Language Models. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 22934–22949, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Knowing but Not Doing: Discourse-level Constraints Adherence of Large Language Models (Hong et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.1083.pdf