Zero-shot fine-grained emotion recognition (FER) is pivotal for empathetic AI but remains constrained by two inherent limitations in retrieval-augmented in-context learning (ICL): 1) subtle emotional distinctions inject semantic noise that blurs decision boundaries, and 2) naive similarity-based retrieval often surfaces counterproductive or antonymous demonstrations. To address these, we propose EmoDap, a dual-agent prompt retrieval framework for zero-shot FER. EmoDap first constructs a high-quality demonstration pool via self-consistency pseudo-labeling and derives explicit emotion prototypes through contrastive learning. Subsequently, a demonstration retriever and an emotion predictor are jointly optimized via Group Relative Policy Optimization (GRPO): the retriever learns to select examples that maximize the predictor’s accuracy, while the predictor leverages prototype guidance to dynamically filter candidate emotions. Extensive experiments across four benchmarks demonstrate that EmoDap consistently outperforms state-of-the-art baselines, establishing a robust paradigm for zero-shot FER driven by open-source LLM backbones.

Current Emotion Recognition in Conversation (ERC) research follows a closed-domain assumption. However, there is no clear consensus on emotion classification in psychology, which presents a challenge for models when it comes to recognizing previously unseen emotions in real-world applications. To bridge this gap, we introduce the Unseen Emotion Recognition in Conversation (UERC) task for the first time and propose ProEmoTrans, a solid prototype-based emotion transfer framework. This prototype-based approach shows promise but still faces key challenges: First, implicit expressions complicate emotion definition, which we address by proposing an LLM-enhanced description approach. Second, utterance encoding in long conversations is difficult, which we tackle with a proposed parameter-free mechanism for efficient encoding and overfitting prevention. Finally, the Markovian flow nature of emotions is hard to transfer, which we address with an improved Attention Viterbi Decoding (AVD) method to transfer seen emotion transitions to unseen emotions. Extensive experiments on three datasets show that our method serves as a strong baseline for preliminary exploration in this new area.