We have been using personal assistants (PA) coupled with multi-agent systems (MASs) in several CSCW applications. Since we are considering professional environments, where users have many tasks to perform, and where users are using several different applications at the same time (browsers, CADs, etc.), the PA interface should motivate users to keep using their assistant. To achieve this goal, we propose WebAnima. WebAnima is a web-based embodied interface agent specially designed to assist team members of a CSCW application during their daily work based on computers. In WebAnima, the intelligent behaviour is guaranteed thanks to a conversational interface and ontologies that support semantic interpretation. We believe that embodied conversational assistants will improve the quality of assistance and increase collaboration between project members. With WebAnima, we expect to acquire information that can be further processed and reused in current and subsequent projects aiming at increasing productivity. In this paper, we present the embodied conversational assistant and its insertion into an MAS designed for research and development projects. We describe the design of the agent, highlighting the role of ontologies for semantic interpretation and the dynamic behaviour of the embodied animated agent.