LQ-Rewriter: Generative Reward Model-Guided Lazy Query Rewriting for Role-Playing Dialogue

Wei Song, Zheng Huang, Renyu Zhu, Runze Wu, Zhenya Huang, Yihuan Mao, Rongsheng Zhang, Tangjie Lv, Kai Zhang


Abstract
With the rapid development of large language models (LLMs), role-playing dialogue systems have become increasingly popular for immersive and personalized human–AI interaction. However, in real-world role-playing scenarios, users often provide lazy queries—brief and ambiguous responses such as "oh," "hmm," or "?"—which lack explicit intent and emotional cues, making it difficult for role-playing LLMs to generate engaging replies. Existing query rewriting methods mainly target functional tasks such as information retrieval and are not tailored to role-playing dialogue, where rewrite quality depends on role-playing-specific factors such as character consistency and personalized user preferences. To address this, we first propose a listwise Generative Reward Model (GRM) trained from real user preference data collected through online regeneration behavior, which provides fine-grained process and final preference signals for training a Lazy Query Rewriter. Using rejection fine-tuning and reinforcement learning, the LQ-Rewriter learns to transform underspecified user inputs into richer expressions while preserving user intent and dialogue context. Experiments on real-world dialogue logs from a mainstream Chinese AI-powered romantic role-playing platform show that our GRM substantially outperforms general-purpose LLM judges. Moreover, our LQ-Rewriter achieves the highest GRM-based and human preference win rates among all rewriting baselines, and brings tangible improvements in online deployment.
Anthology ID:
2026.emnlp-main.391
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:
8977–8994
Language:
URL:
https://aclanthology.org/2026.emnlp-main.391/
DOI:
Bibkey:
Cite (ACL):
Wei Song, Zheng Huang, Renyu Zhu, Runze Wu, Zhenya Huang, Yihuan Mao, Rongsheng Zhang, Tangjie Lv, and Kai Zhang. 2026. LQ-Rewriter: Generative Reward Model-Guided Lazy Query Rewriting for Role-Playing Dialogue. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 8977–8994, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
LQ-Rewriter: Generative Reward Model-Guided Lazy Query Rewriting for Role-Playing Dialogue (Song et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.391.pdf