Call, Reward, Repeat: Advancing Dialog State Tracking with GRPO and Function Calling

Timur Ionov, Anna Marshalova, Valentin Malykh


Abstract
Recent advancements in Large Language Models (LLMs) have notably enhanced task-oriented dialogue systems, particularly in Dialogue State Tracking (DST), owing to their generative capabilities and strong generalization. Although recent approaches such as LDST and FnCTOD significantly improved cross-domain DST performance via supervised fine-tuning (SFT), these methods typically require substantial amounts of domain-specific data. In this paper, we address this limitation by employing Group Relative Policy Optimization (GRPO) - a critic-free reinforcement learning method that efficiently guides LLMs toward improved DST accuracy even under low-resource conditions. Our results on established DST benchmarks, including MultiWOZ 2.1 and 2.4, demonstrate that the RL approach achieves superior performance to existing methods while using significantly reduced out-of-domain training data. In addition, we found out that models pretrained specifically for tool-use tasks can be a better starting point, especially on small scales.
Anthology ID:
2026.eacl-srw.21
Volume:
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 4: Student Research Workshop)
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Selene Baez Santamaria, Sai Ashish Somayajula, Atsuki Yamaguchi
Venue:
EACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
292–303
Language:
URL:
https://preview.aclanthology.org/ingest-eacl/2026.eacl-srw.21/
DOI:
Bibkey:
Cite (ACL):
Timur Ionov, Anna Marshalova, and Valentin Malykh. 2026. Call, Reward, Repeat: Advancing Dialog State Tracking with GRPO and Function Calling. In Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 4: Student Research Workshop), pages 292–303, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
Call, Reward, Repeat: Advancing Dialog State Tracking with GRPO and Function Calling (Ionov et al., EACL 2026)
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PDF:
https://preview.aclanthology.org/ingest-eacl/2026.eacl-srw.21.pdf