In this paper, we present our approach to personalize existing and various animated agents, taking into account the context and the users’ knowledge, abilities and preferences. For this purpose, we propose a grammar to describe animated agents in a common formalism, and specify their characteristics and abilities. According to this description, it is then possible to define actions with parameters that can be used and personalized in a description of the required assistance for a given application, which is used by a generic assistant to provide each user with personalized assistance.