WEREWOLF: Reputation-Aware Red-Teaming for Self-Organizing LLM Multi-Agent Systems

Manhin Poon, Qirun Zeng, Xiangxiang Dai, Jinhang Zuo


Abstract
Self-organizing LLM-based multi-agent systems dynamically select agents and organize communication graphs for each query. While this adaptivity improves flexibility, it also creates a control-plane attack surface: a malicious agent may exploit this selection and organization process to preserve future access and influence over later tasks. We formulate the attacker as a reputation-aware Trojan agent that chooses when to behave constructively and when to disrupt the task. Under full reputation access, we prove the optimality of a threshold-based attack policy and show why persistent attacks require a survivability constraint. We then propose WEREWOLF, a primal-dual reinforcement learning attacker that learns attack timing under hidden reputation by maximizing task disruption subject to control-plane access loss. Across four self-organizing systems and three benchmarks, it reduces average accuracy from 72.3% to 25.8% with an 86.3% attack success rate, and retains control-plane exposure comparable to that of honest agents.
Anthology ID:
2026.findings-emnlp.2427
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:
52105–52116
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2427/
DOI:
Bibkey:
Cite (ACL):
Manhin Poon, Qirun Zeng, Xiangxiang Dai, and Jinhang Zuo. 2026. WEREWOLF: Reputation-Aware Red-Teaming for Self-Organizing LLM Multi-Agent Systems. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 52105–52116, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
WEREWOLF: Reputation-Aware Red-Teaming for Self-Organizing LLM Multi-Agent Systems (Poon et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2427.pdf