Debating the Unspoken: Role-Anchored Multi-Agent Reasoning for Half-Truth Detection

Yixuan Tang, Yirui Zhang, Hang Feng, Anthony Kum Hoe Tung


Abstract
Half-truths, claims that are factually correct yet misleading due to omitted context, remain a blind spot for fact verification systems focused on explicit falsehoods. Addressing such omission-based manipulation requires reasoning not only about what is said, but also about what is left unsaid. We propose RADAR, a role-anchored multi-agent debate framework for omission-aware fact verification under realistic, noisy retrieval. RADAR assigns complementary roles to a Politician and a Scientist, who reason adversarially over shared retrieved evidence, moderated by a neutral Judge. A dual-threshold early termination controller adaptively decides when sufficient reasoning has been reached to issue a verdict. Experiments show that RADAR consistently outperforms strong single- and multi-agent baselines across datasets and backbones, improving omission detection accuracy while reducing reasoning cost. These results demonstrate that role-anchored, retrieval-grounded debate with adaptive control is an effective and scalable framework for uncovering missing context in fact verification. The code is available at https://github.com/tangyixuan/RADAR.
Anthology ID:
2026.emnlp-main.1438
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:
32858–32872
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1438/
DOI:
Bibkey:
Cite (ACL):
Yixuan Tang, Yirui Zhang, Hang Feng, and Anthony Kum Hoe Tung. 2026. Debating the Unspoken: Role-Anchored Multi-Agent Reasoning for Half-Truth Detection. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 32858–32872, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Debating the Unspoken: Role-Anchored Multi-Agent Reasoning for Half-Truth Detection (Tang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1438.pdf