AlignUSER: Human-Aligned LLM Agents via World Models for Recommender System Evaluation

Fuente: arXiv
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Autores principales: Bougie, Nicolas, Marconi, Gian Maria, Yip, Tony, Watanabe, Narimasa
Formato: Preprint
Publicado: 2026
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author Bougie, Nicolas
Marconi, Gian Maria
Yip, Tony
Watanabe, Narimasa
author_facet Bougie, Nicolas
Marconi, Gian Maria
Yip, Tony
Watanabe, Narimasa
contents Evaluating recommender systems remains challenging due to the gap between offline metrics and real user behavior, as well as the scarcity of interaction data. Recent work explores large language model (LLM) agents as synthetic users, yet they typically rely on few-shot prompting, which yields a shallow understanding of the environment and limits their ability to faithfully reproduce user actions. We introduce AlignUSER, a framework that learns world-model-driven agents from human interactions. Given rollout sequences of actions and states, we formalize world modeling as a next state prediction task that helps the agent internalize the environment. To align actions with human personas, we generate counterfactual trajectories around demonstrations and prompt the LLM to compare its decisions with human choices, identify suboptimal actions, and extract lessons. The learned policy is then used to drive agent interactions with the recommender system. We evaluate AlignUSER across multiple datasets and demonstrate closer alignment with genuine humans than prior work, both at the micro and macro levels.
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publishDate 2026
record_format arxiv
spellingShingle AlignUSER: Human-Aligned LLM Agents via World Models for Recommender System Evaluation
Bougie, Nicolas
Marconi, Gian Maria
Yip, Tony
Watanabe, Narimasa
Information Retrieval
Artificial Intelligence
Evaluating recommender systems remains challenging due to the gap between offline metrics and real user behavior, as well as the scarcity of interaction data. Recent work explores large language model (LLM) agents as synthetic users, yet they typically rely on few-shot prompting, which yields a shallow understanding of the environment and limits their ability to faithfully reproduce user actions. We introduce AlignUSER, a framework that learns world-model-driven agents from human interactions. Given rollout sequences of actions and states, we formalize world modeling as a next state prediction task that helps the agent internalize the environment. To align actions with human personas, we generate counterfactual trajectories around demonstrations and prompt the LLM to compare its decisions with human choices, identify suboptimal actions, and extract lessons. The learned policy is then used to drive agent interactions with the recommender system. We evaluate AlignUSER across multiple datasets and demonstrate closer alignment with genuine humans than prior work, both at the micro and macro levels.
title AlignUSER: Human-Aligned LLM Agents via World Models for Recommender System Evaluation
topic Information Retrieval
Artificial Intelligence
url https://arxiv.org/abs/2601.00930