[2603.02229] Safety Training Persists Through Helpfulness Optimization in LLM Agents

Computer Science > Machine Learning arXiv:2603.02229 (cs) [Submitted on 13 Feb 2026] Title:Safety Training Persists Through Helpfulness Optimization in LLM Agents Authors:Benjamin Plaut View a PDF of the paper titled Safety Training Persists Through Helpfulness Optimization in LLM Agents, by Benjamin Plaut View PDF HTML (experimental) Abstract:Safety post-training has been studied extensively in single-step "chat" settings where safety typically refers to refusing harmful requests. We study an "agentic" (i.e., multi-step, tool-use) setting where safety refers to harmful actions directly taken by the LLM. We compare the effects of running direct preference optimization (DPO) on safety or helpfulness alone vs both metrics sequentially. As expected, training on one metric alone results in an extreme point along this frontier. However, unlike prior work, we find that safety training persists through subsequent helpfulness training. We also find that all training configurations end up near a linear Pareto frontier with $R^2 = 0.77$. Even post-training on both metrics simultaneously simply results in another point on the frontier rather than finding a "best of both worlds" strategy, despite the presence of such strategies in our DPO dataset. Overall, our findings underscore the need for better understanding of post-training dynamics. Comments: Subjects: Machine Learning (cs.LG); Computation and Language (cs.CL) Cite as: arXiv:2603.02229 [cs.LG]   (or arXiv:2603.02229v1 [cs.LG] f...