ProTOD: Proactive Task-oriented Dialogue System Based on Large Language Model

Wenjie Dong, Sirong Chen, Yan Yang


Abstract
Large Language Model (LLM)-based Task-Oriented Dialogue (TOD) systems show promising performance in helping users achieve specific goals in a zero-shot setting. However, existing systems engage with users in a reactive manner, relying on a basic single-query mechanism with the knowledge base and employing passive policy planning. The proactive TOD systems, which can provide potentially helpful information and plan cross-domain multi-task dialogue policies, have not been well studied. In addition, effective evaluation methods are also lacking. To address these issues, we propose ProTOD, a novel LLM-based proactive TOD framework designed to improve system proactivity and goal completion. First, we design an adaptive exploratory retrieval mechanism to dynamically navigate domain knowledge. Second, we introduce a two-stage passive-to-proactive policy planner that effectively organizes knowledge and actions relationship. Finally, we develop two distinct user simulators with different personalities to simulate real-world interactions and propose a new error measure called Human-targeted Policy Edit Rate (HPER) for evaluation. Experimental results show that ProTOD achieves state-of-the-art (SOTA) performance, improving goal completion rates by 10% while significantly enhancing the proactive engagement.
Anthology ID:
2025.coling-main.614
Volume:
Proceedings of the 31st International Conference on Computational Linguistics
Month:
January
Year:
2025
Address:
Abu Dhabi, UAE
Editors:
Owen Rambow, Leo Wanner, Marianna Apidianaki, Hend Al-Khalifa, Barbara Di Eugenio, Steven Schockaert
Venue:
COLING
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
9147–9164
Language:
URL:
https://aclanthology.org/2025.coling-main.614/
DOI:
Bibkey:
Cite (ACL):
Wenjie Dong, Sirong Chen, and Yan Yang. 2025. ProTOD: Proactive Task-oriented Dialogue System Based on Large Language Model. In Proceedings of the 31st International Conference on Computational Linguistics, pages 9147–9164, Abu Dhabi, UAE. Association for Computational Linguistics.
Cite (Informal):
ProTOD: Proactive Task-oriented Dialogue System Based on Large Language Model (Dong et al., COLING 2025)
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PDF:
https://aclanthology.org/2025.coling-main.614.pdf