Behavior2Trip: Towards Personalized Travel Planning via User Behavior Trajectory

Zihao Cheng, Yingyu Shan, Hongru Wang, Zeming Liu, Xinyi Wang, Xiangrong Zhu, Yuhang Guo, Wei Lin, Yunhong Wang


Abstract
Travel planning agents assist users in generating personalized travel plans by modeling their individual preferences. Existing agents either rely on explicit user instructions or engage in multi-turn clarification to elicit user preferences. However, both approaches overlook the rich behavioral signals latent in users’ past behaviors, which implicitly encode their preferences. This over-reliance on active user input increases interaction burden and limits plan personalization. To bridge this gap, we introduce a new task, **Behavior-Aware Travel Planning**, which infers user preferences directly from past behaviors and generates personalized travel plans. To facilitate research on this task, we introduce **Behavior2Trip**, a benchmark constructed from one of the largest Chinese online travel platforms, comprising 11,400 instances. Each instance represents an average of 39.8 past user behaviors spanning 14 attributes across 5 preference dimensions. We further propose **B2T-Agent**, a reinforcement learning-based agent that leverages user behavior trajectories, interacts with external tools for preference-aligned retrieval, and maintains an internal memory module. Experiments on Behavior2Trip show that GPT-4.1 achieves a full-constraint pass rate of only 0.5% on the hardest tasks, while B2T-Agent built upon Qwen3-8B outperforms all baselines, highlighting the substantial challenge of this task. Moreover, Qwen3-8B trained with B2T-Agent also outperforms GPT-4.1 on the TravelPlanner benchmark, demonstrating strong generalization.
Anthology ID:
2026.findings-emnlp.1509
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:
32110–32131
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URL:
https://aclanthology.org/2026.findings-emnlp.1509/
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Cite (ACL):
Zihao Cheng, Yingyu Shan, Hongru Wang, Zeming Liu, Xinyi Wang, Xiangrong Zhu, Yuhang Guo, Wei Lin, and Yunhong Wang. 2026. Behavior2Trip: Towards Personalized Travel Planning via User Behavior Trajectory. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 32110–32131, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Behavior2Trip: Towards Personalized Travel Planning via User Behavior Trajectory (Cheng et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1509.pdf