Metaverse aims at connecting the physical and digital world in a highly immersive virtual environment that can replicate society and social practices within it. It is populated not only by avatars corresponding to users but also by nonplayer characters (NPCs). These virtual agents should be able to perceive other agents and objects in the scene, reason and act preferably by exhibiting credible and acceptable social behavior. Relying on the Social Practice theory, this work proposes an architecture for the design and development of a virtual agent able to understand social practices in the Metaverse and act by respecting the social norms that the circumstances entail. The agent is equipped with modules for recognizing elements of the scene, knowledge and rules about a set of social practices. The scene information is exploited by a reasoning module that allows the agent to evaluate the current social practice, socially interpret the events, and activate the most appropriate behaviors. The paper describes the proposed architecture, its implementation, and the realization of an experimental virtual scenario.