How Order-Sensitive Are LLMs? OrderProbe for Deterministic Structural Reconstruction

Zhaolu Kang, Yingjie He, Kehan Jiang, Leqi Zheng, Jiachen Qian, Qianyuan Zhang, Chunlei Meng, Yujie Feng, Yuan Wang, Stephen Dou, Aming Wu, Pengxiang Zhao, Jiaxin Liu, Guansu Wang, Zeyu Zhang, Zeyu Wang, Lei Wang, Qishi Zhan, Xiaomin He, Meisheng Zhang, Jianyuan Ni, Richeng Xuan


Abstract
Large language models (LLMs) excel at semantic understanding, yet their ability to reconstruct internal structure from scrambled inputs remains underexplored. Sentence-level restoration is difficult to evaluate automatically because scrambled sentences often admit multiple valid reorderings. We introduce OrderProbe, a deterministic benchmark for structural reconstruction using fixed four-character expressions in Chinese, Japanese, and Korean, which have a unique canonical order and thus support exact-match scoring. We further propose a diagnostic framework that evaluates models beyond recovery accuracy, including Semantic Accuracy, Logical Validity, Structural Consistency, Robustness, and Information Density. Experiments on twelve widely used LLMs show that structural reconstruction remains difficult even for frontier systems: zero-shot recovery frequently falls below 35%. We also observe a consistent gap between meaning-oriented generation and exact structural reconstruction, suggesting that structural robustness is not an automatic byproduct of semantic competence.
Anthology ID:
2026.findings-emnlp.788
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
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Pages:
16651–16681
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URL:
https://aclanthology.org/2026.findings-emnlp.788/
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Cite (ACL):
Zhaolu Kang, Yingjie He, Kehan Jiang, Leqi Zheng, Jiachen Qian, Qianyuan Zhang, Chunlei Meng, Yujie Feng, Yuan Wang, Stephen Dou, Aming Wu, Pengxiang Zhao, Jiaxin Liu, Guansu Wang, Zeyu Zhang, Zeyu Wang, Lei Wang, Qishi Zhan, Xiaomin He, Meisheng Zhang, Jianyuan Ni, and Richeng Xuan. 2026. How Order-Sensitive Are LLMs? OrderProbe for Deterministic Structural Reconstruction. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 16651–16681, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
How Order-Sensitive Are LLMs? OrderProbe for Deterministic Structural Reconstruction (Kang et al., Findings 2026)
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https://aclanthology.org/2026.findings-emnlp.788.pdf