Task-Oriented Dialogue Systems through Function Calling

Tiziano Labruna, Giovanni Bonetta, Bernardo Magnini


Abstract
Large Language Models (LLMs) have demonstrated remarkable capabilities in generating dialogues and handling a broad range of user queries. However, their effectiveness as end-to-end Task-Oriented Dialogue (TOD) systems remains limited due to their reliance on static parametric memory, which fails to accommodate evolving knowledge bases (KBs). This paper investigates a scalable function-calling approach that enables LLMs to retrieve only the necessary KB entries via schema-guided queries, rather than embedding the entire KB into each prompt. This selective retrieval strategy reduces prompt size and inference time while improving factual accuracy in system responses. We evaluate our method on the MultiWOZ 2.3 dataset and compare it against a full-KB baseline that injects the entire KB into every prompt. Experimental results show that our approach consistently outperforms the full-KB method in accuracy, while requiring significantly fewer input tokens and considerably less computation time, especially when the KB size increases.
Anthology ID:
2025.ranlp-1.72
Volume:
Proceedings of the 15th International Conference on Recent Advances in Natural Language Processing - Natural Language Processing in the Generative AI Era
Month:
September
Year:
2025
Address:
Varna, Bulgaria
Editors:
Galia Angelova, Maria Kunilovskaya, Marie Escribe, Ruslan Mitkov
Venue:
RANLP
SIG:
Publisher:
INCOMA Ltd., Shoumen, Bulgaria
Note:
Pages:
614–622
Language:
URL:
https://aclanthology.org/2025.ranlp-1.72/
DOI:
Bibkey:
Cite (ACL):
Tiziano Labruna, Giovanni Bonetta, and Bernardo Magnini. 2025. Task-Oriented Dialogue Systems through Function Calling. In Proceedings of the 15th International Conference on Recent Advances in Natural Language Processing - Natural Language Processing in the Generative AI Era, pages 614–622, Varna, Bulgaria. INCOMA Ltd., Shoumen, Bulgaria.
Cite (Informal):
Task-Oriented Dialogue Systems through Function Calling (Labruna et al., RANLP 2025)
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PDF:
https://aclanthology.org/2025.ranlp-1.72.pdf