DynSess: Dynamic Session-Level Evaluation and Optimization Framework for Role-Playing Agents

Rongsheng Zhang, Jiji Tang, Junnan Ren, Zuyi Bao, Weijie Chen, Ruofan Hu, Tangjie Lv, Zhou Zhao, Yan Zhang


Abstract
Role-playing with large language models is fundamentally a *session-level* task, requiring agents to sustain character identity and interaction quality across extended multi-turn conversations. Yet existing evaluation and optimization methods remain largely turn-level, failing to capture long-horizon quality. We propose **DynSess**, a unified session-level framework for role-playing agents. **DynSess-Eval** scores complete dialogue sessions via rubrics targeting long-horizon behaviors. Leveraging its session-level rewards, we construct high-quality training trajectories through multi-turn lookahead search and train **DynSess-Character** with two complementary variants: DSPO (off-policy) and GSRPO (on-policy). Experiments show that DynSess-Eval aligns with human judgments substantially better than prior evaluators, and blind human evaluation further shows that DynSess-Character matches the strongest character model despite using substantially fewer parameters, while maintaining strong role consistency and interactive ability. The dataset and code are publicly available in https://github.com/Collab-Gen/DynSess.
Anthology ID:
2026.findings-emnlp.689
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
14443–14461
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URL:
https://aclanthology.org/2026.findings-emnlp.689/
DOI:
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Cite (ACL):
Rongsheng Zhang, Jiji Tang, Junnan Ren, Zuyi Bao, Weijie Chen, Ruofan Hu, Tangjie Lv, Zhou Zhao, and Yan Zhang. 2026. DynSess: Dynamic Session-Level Evaluation and Optimization Framework for Role-Playing Agents. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 14443–14461, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
DynSess: Dynamic Session-Level Evaluation and Optimization Framework for Role-Playing Agents (Zhang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.689.pdf