Empathy relies on the cognitive capacity to relate to similar past experiences. Consequently, retrieval-based approaches utilize analogous exemplars to guide empathetic dialogue generation. However, existing methods prioritize semantic similarity over emotion characteristics, often leading to unempathetic responses. To address this, we propose REG, a framework that integrates four Emotion Attributes into the retrieval process to ensure explicit emotional alignment. Furthermore, to mitigate the noise and limited diversity caused by coarse-grained sentence-level attributes, we incorporate Token-level Retrieval for finer granularity and a Retrieval Candidate Augmentation strategy to enhance diversity. Empirical results on the EmpatheticDialogues dataset demonstrate that REG significantly outperforms baselines, offering a robust solution for empathetic generation.

Large language models (LLMs) are vulnerable to adversarial attacks even in strict black-box settings with only hard-label feedback.Existing attacks suffer from inefficient search due to lack of informative signals such as logits or probabilities. In this work, we propose Prompt-Guided Ensemble Attack (PGEA), a novel black-box framework that leverages prompt-induced confidence, which reflects variations in a model’s self-assessed certainty across different prompt templates, as an auxiliary signal to guide attacks. We first demonstrate that confidence estimates vary significantly with prompt phrasing despite unchanged predictions. We then integrate these confidence signals in a two-stage attack: (1) estimating token-level vulnerability via confidence elicitation, and (2) applying ensemble word-level substitutions guided by these estimates. Experiments on LLaMA-3-8B-Instruct and Mistral-7B-Instruct-v0.3 on three classification tasks show that PGEA improves the attack success rate and query efficiency while maintaining semantic fidelity. Our results highlight that verbalized confidence, even without access to probabilities, is a valuable and underexplored signal for black-box adversarial attacks. The code is available at https://github.com/cmn-bits/PGEA-main.

Large Language Models (LLMs) have made remarkable advances in role-playing dialogue agents, demonstrating their utility in character simulations. However, it remains challenging for these agents to balance character portrayal utility with content safety because this essential character simulation often comes with the risk of generating unsafe content. To address this issue, we first conduct a systematic exploration of the safety-utility trade-off across multiple LLMs. Our analysis reveals that risk scenarios created by villain characters and user queries (referred to as risk coupling) contribute to this trade-off. Building on this, we propose a novel Adaptive Dynamic Multi-Preference (ADMP) method, which dynamically adjusts safety-utility preferences based on the degree of risk coupling and guides the model to generate responses biased toward utility or safety. We further introduce Coupling Margin Sampling (CMS) into coupling detection to enhance the model’s ability to handle high-risk scenarios. Experimental results demonstrate that our approach improves safety metrics while maintaining utility.

High-quality prompts are crucial for eliciting outstanding performance from large language models (LLMs) on complex tasks. Existing research has explored model-driven strategies for prompt optimization. However, these methods often suffer from high computational overhead or require strong optimization capabilities from the model itself, which limits their broad applicability.To address these challenges, we propose ORPP, a framework that enhances model performance by optimizing and generating role-playing prompts. The core idea of ORPP is to confine the prompt search space to role-playing scenarios, thereby fully activating the model’s intrinsic capabilities through carefully crafted, high-quality role-playing prompts. Specifically, ORPP first performs iterative optimization on a small subset of training samples to generate high-quality role-playing prompts. Then, leveraging the model’s few-shot learning capability, it transfers the optimization experience to efficiently generate suitable prompts for the remaining samples.Our experimental results show that ORPP not only matches but in most cases surpasses existing mainstream prompt optimization methods in terms of performance. Notably, ORPP suggests great “plug-and-play” capability. In most cases, it can be integrated with various other prompt methods and further enhance their effectiveness.