One Agent to Serve All: a Lite-Adaptive Stylized AI Assistant for Millions of Multi-Style Official Accounts

Conversational agents deployed in industrialscale WeChat Official Account platforms must generate responses that are both contextually grounded and stylistically aligned-requirements that existing methods struggle to meet.Chain-of-thought (CoT) prompting induces significant latency due to multi-turn reasoning; per-account finetuning is computationally prohibitive; and long prompt-based methods degrade the model's ability to grasp injected context and style.In this paper, we propose WeStar, a lite-adaptive framework for stylized contextual question answering that scales to millions of WeChat Official Accounts.Our contributions are fourfold: (1) We introduce WeStar, a unified framework capable of serving large volumes of official accounts with minimal overhead.(2) We propose a multi-dimensional, cluster-based parameter sharing scheme that enables compact style representation while preserving stylistic diversity.(3) We develop a style-enhanced Direct Preference Optimization (SeDPO) method to optimize each style cluster's parameters for improved generation quality.(4) Experiments on a large-scale industrial dataset validate the effectiveness and efficiency of WeStar, underscoring its pracitical value in real-world deployment.