WebEvolver: Enhancing Web Agent Self-Improvement with Coevolving World Model

Fuente: arXiv
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Main Authors: Fang, Tianqing, Zhang, Hongming, Zhang, Zhisong, Ma, Kaixin, Yu, Wenhao, Mi, Haitao, Yu, Dong
Format: Preprint
Published: 2025
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author Fang, Tianqing
Zhang, Hongming
Zhang, Zhisong
Ma, Kaixin
Yu, Wenhao
Mi, Haitao
Yu, Dong
author_facet Fang, Tianqing
Zhang, Hongming
Zhang, Zhisong
Ma, Kaixin
Yu, Wenhao
Mi, Haitao
Yu, Dong
contents Agent self-improvement, where the backbone Large Language Model (LLM) of the agent are trained on trajectories sampled autonomously based on their own policies, has emerged as a promising approach for enhancing performance. Recent advancements, particularly in web environments, face a critical limitation: their performance will reach a stagnation point during autonomous learning cycles, hindering further improvement. We argue that this stems from limited exploration of the web environment and insufficient exploitation of pre-trained web knowledge in LLMs. To improve the performance of self-improvement, we propose a novel framework that introduces a co-evolving World Model LLM. This world model predicts the next observation based on the current observation and action within the web environment. Leveraging LLMs' pretrained knowledge of abundant web content, the World Model serves dual roles: (1) as a virtual web server generating self-instructed training data to continuously refine the agent's policy, and (2) as an imagination engine during inference, enabling look-ahead simulation to guide action selection for the agent LLM. Experiments in real-world web environments (Mind2Web-Live, WebVoyager, and GAIA-web) show a 10% performance gain over existing self-evolving agents, demonstrating the efficacy and generalizability of our approach, without using any distillation from more powerful close-sourced models. Our work establishes the necessity of integrating world models into autonomous agent frameworks to unlock sustained adaptability. Code is available at https://github.com/Tencent/SelfEvolvingAgent
format Preprint
id arxiv_https___arxiv_org_abs_2504_21024
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle WebEvolver: Enhancing Web Agent Self-Improvement with Coevolving World Model
Fang, Tianqing
Zhang, Hongming
Zhang, Zhisong
Ma, Kaixin
Yu, Wenhao
Mi, Haitao
Yu, Dong
Computation and Language
Agent self-improvement, where the backbone Large Language Model (LLM) of the agent are trained on trajectories sampled autonomously based on their own policies, has emerged as a promising approach for enhancing performance. Recent advancements, particularly in web environments, face a critical limitation: their performance will reach a stagnation point during autonomous learning cycles, hindering further improvement. We argue that this stems from limited exploration of the web environment and insufficient exploitation of pre-trained web knowledge in LLMs. To improve the performance of self-improvement, we propose a novel framework that introduces a co-evolving World Model LLM. This world model predicts the next observation based on the current observation and action within the web environment. Leveraging LLMs' pretrained knowledge of abundant web content, the World Model serves dual roles: (1) as a virtual web server generating self-instructed training data to continuously refine the agent's policy, and (2) as an imagination engine during inference, enabling look-ahead simulation to guide action selection for the agent LLM. Experiments in real-world web environments (Mind2Web-Live, WebVoyager, and GAIA-web) show a 10% performance gain over existing self-evolving agents, demonstrating the efficacy and generalizability of our approach, without using any distillation from more powerful close-sourced models. Our work establishes the necessity of integrating world models into autonomous agent frameworks to unlock sustained adaptability. Code is available at https://github.com/Tencent/SelfEvolvingAgent
title WebEvolver: Enhancing Web Agent Self-Improvement with Coevolving World Model
topic Computation and Language
url https://arxiv.org/abs/2504.21024