TCD: Empowering Zero-Shot Detection of LLM-Generated Text using Token Contextual Dependency

Shihan Ma, Quan Wang


Abstract
Zero-shot detectors for LLM-generated text aggregate token-level statistics uniformly, implicitly assuming that every position contributes equally to detection. We challenge this assumption and show that detection signal is highly uneven across token positions: positions of high contextual dependency, where the surrogate model relies on concentrated context, carry far more discriminative power than others. Using attention entropy to quantify this dependency, we empirically validate that aggregating only low-entropy tokens yields clearly separated human and LLM score distributions, whereas high-entropy tokens do not. Based on this finding, we propose Token Contextual Dependency (TCD), a plug-and-play framework that reweights token contributions in existing zero-shot detectors via attention entropy-based weights computed from dynamically selected layers. Experiments on state-of-the-art detectors across multiple benchmarks demonstrate consistent and meaningful improvements in detection performance. Our code is available at: https://github.com/RecursionM/TCD.
Anthology ID:
2026.emnlp-main.1708
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
38911–38926
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1708/
DOI:
Bibkey:
Cite (ACL):
Shihan Ma and Quan Wang. 2026. TCD: Empowering Zero-Shot Detection of LLM-Generated Text using Token Contextual Dependency. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 38911–38926, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
TCD: Empowering Zero-Shot Detection of LLM-Generated Text using Token Contextual Dependency (Ma & Wang, EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1708.pdf