SalesSim: Benchmarking and Aligning Multimodal Language Models as Retail User Simulators

Fuente: arXiv
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Autores principales: Pruksachatkun, Yada, Wan, Elaine, Chen, Lyanna, Chang, Kai-Wei, Wu, Chien-Sheng
Formato: Preprint
Publicado: 2026
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author Pruksachatkun, Yada
Wan, Elaine
Chen, Lyanna
Chang, Kai-Wei
Wu, Chien-Sheng
author_facet Pruksachatkun, Yada
Wan, Elaine
Chen, Lyanna
Chang, Kai-Wei
Wu, Chien-Sheng
contents We present SalesSim, a framework and testbed for evaluating the ability of Multimodal Large Language Models (MLLMs) to simulate realistic, persona-driven customer behavior in multi-turn, multi-modal, tool-augmented online retail conversations. Unlike prior work that treat user simulation as surface-level dialogue generation, SalesSim models retail interaction and decision-making as a grounded, agentic process, where shoppers with diverse backgrounds, preferences, and dealbreakers interact with a sales agent, seek clarifications, and make informed purchasing decisions. For evaluation, we design a suite of metrics centered on decision alignment, measuring the consistency between the simulator's actions and its persona specifications, as well as conversational quality. We find several behavioral gaps after benchmarking 6 open and closed-source state-of-the-art models. First, while models produce fluent conversations, they display significantly lower lexical diversity and overdisclosure of criteria across personas compared to human conversations. Second, models tend to be persuaded by sales agent suggestions and drift from persona specifications. Even the strongest model achieves less than 79% average alignment with its underlying persona specifications. To make progress on these limitations, we propose UserGRPO, a multi-turn, multi-objective reinforcement learning recipe to optimize both conversational fluency and decision alignment under persona specifications. Our experiments demonstrate that UserGRPO boosts decision alignment of the baseline model by 13.8% while improving conversational quality. By introducing SalesSim, we provide a new testbed for the community to investigate and improve the adherence of user simulators in goal-oriented settings.
format Preprint
id arxiv_https___arxiv_org_abs_2605_08334
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle SalesSim: Benchmarking and Aligning Multimodal Language Models as Retail User Simulators
Pruksachatkun, Yada
Wan, Elaine
Chen, Lyanna
Chang, Kai-Wei
Wu, Chien-Sheng
Computation and Language
We present SalesSim, a framework and testbed for evaluating the ability of Multimodal Large Language Models (MLLMs) to simulate realistic, persona-driven customer behavior in multi-turn, multi-modal, tool-augmented online retail conversations. Unlike prior work that treat user simulation as surface-level dialogue generation, SalesSim models retail interaction and decision-making as a grounded, agentic process, where shoppers with diverse backgrounds, preferences, and dealbreakers interact with a sales agent, seek clarifications, and make informed purchasing decisions. For evaluation, we design a suite of metrics centered on decision alignment, measuring the consistency between the simulator's actions and its persona specifications, as well as conversational quality. We find several behavioral gaps after benchmarking 6 open and closed-source state-of-the-art models. First, while models produce fluent conversations, they display significantly lower lexical diversity and overdisclosure of criteria across personas compared to human conversations. Second, models tend to be persuaded by sales agent suggestions and drift from persona specifications. Even the strongest model achieves less than 79% average alignment with its underlying persona specifications. To make progress on these limitations, we propose UserGRPO, a multi-turn, multi-objective reinforcement learning recipe to optimize both conversational fluency and decision alignment under persona specifications. Our experiments demonstrate that UserGRPO boosts decision alignment of the baseline model by 13.8% while improving conversational quality. By introducing SalesSim, we provide a new testbed for the community to investigate and improve the adherence of user simulators in goal-oriented settings.
title SalesSim: Benchmarking and Aligning Multimodal Language Models as Retail User Simulators
topic Computation and Language
url https://arxiv.org/abs/2605.08334