TRACE: Trajectory Aware Reasoning for Multi-Turn Adversarial Conversation Evaluation.

Md Messal Monem Miah, Adrita Anika, Zhiyuan Yu, Ruihong Huang


Abstract
Multi-turn jailbreak attacks have emerged as a critical safety threat to LLMs, as the harmful objective is decomposed across a sequence of apparently benign turns to bypass guardrails. Existing defenses lack the reasoning capacity to identify evolving manipulation patterns, often trading helpfulness for safety by over-refusing benign requests related to sensitive topics. We introduce Trace, a multi-turn defense with trajectory-aware structured reasoning. Before generating each response, the model identifies manipulation cues from the trajectory, evaluates both the benign and adversarial interpretations of user intent, assigns a jailbreak score, and commits to an action: Allow, Caution, or Decline. We curate 4k multi-turn adversarial conversations from five attack frameworks, pair them with 2.4k benign dialogs, and 600 sensitive-but-benign conversations. We train Llama-3.1-8B-Instruct with SFT and GRPO under a multi-component reward that jointly optimizes helpfulness on benign prompts and robustness against jailbreak attempts. Across seven multi-turn attack benchmarks, Trace attains an average attack success rate (ASR) of 14.5% against 31.4% for the strongest baseline and 74.9% for the undefended target while raising the attacker effort required per successful jailbreak significantly. Trace also balances usability and safety, achieving a 93.3% average compliance on over-refusal benchmarks.
Anthology ID:
2026.emnlp-main.2697
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:
61341–61371
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2697/
DOI:
Bibkey:
Cite (ACL):
Md Messal Monem Miah, Adrita Anika, Zhiyuan Yu, and Ruihong Huang. 2026. TRACE: Trajectory Aware Reasoning for Multi-Turn Adversarial Conversation Evaluation.. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 61341–61371, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
TRACE: Trajectory Aware Reasoning for Multi-Turn Adversarial Conversation Evaluation. (Miah et al., EMNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.emnlp-main.2697.pdf