X-Teaming Evolutionary M2S: Automated Discovery of Multi-turn to Single-turn Jailbreak Templates
Hyunjun Kim , Junwoo Ha , Sangyoon Yu , Haon Park
Published on arXiv
2509.08729
Prompt Injection
OWASP LLM Top 10 — LLM01
Key Finding
Achieves 44.8% jailbreak success rate (103/230) on GPT-4.1 using five generations of evolutionarily optimized M2S templates, producing two new template families.
X-Teaming Evolutionary M2S
Novel technique introduced
Multi-turn-to-single-turn (M2S) compresses iterative red-teaming into one structured prompt, but prior work relied on a handful of manually written templates. We present X-Teaming Evolutionary M2S, an automated framework that discovers and optimizes M2S templates through language-model-guided evolution. The system pairs smart sampling from 12 sources with an LLM-as-judge inspired by StrongREJECT and records fully auditable logs. Maintaining selection pressure by setting the success threshold to $θ= 0.70$, we obtain five evolutionary generations, two new template families, and 44.8% overall success (103/230) on GPT-4.1. A balanced cross-model panel of 2,500 trials (judge fixed) shows that structural gains transfer but vary by target; two models score zero at the same threshold. We also find a positive coupling between prompt length and score, motivating length-aware judging. Our results demonstrate that structure-level search is a reproducible route to stronger single-turn probes and underscore the importance of threshold calibration and cross-model evaluation. Code, configurations, and artifacts are available at https://github.com/hyunjun1121/M2S-x-teaming.
Key Contributions
- Automated evolutionary framework that discovers and optimizes multi-turn-to-single-turn (M2S) jailbreak templates using LLM-guided mutation and selection
- LLM-as-judge evaluation pipeline inspired by StrongREJECT with fully auditable logs, sampling from 12 jailbreak sources across five evolutionary generations
- Cross-model evaluation (2,500 trials) demonstrating structural gains transfer across targets and revealing a positive coupling between prompt length and jailbreak success score