Abstract. We present a service-oriented personalization system, set in an educational framework, based on a semantic annotation of courses, given at a knowledge level (what the course teaches, what is requested to know for attending it in a profitable way). The system supports users in building personalized curricula, formalized by means of an action theory. It is also possible to verify the compliance of curricula w.r.t. a model, expressing constraints at a knowledge level. For what concerns the first task, classical planning techniques are adopted, which take into account both the student’s initial knowledge and her learning goal. Instead, curricula validation is done against a model, formalized as a set of temporal constraints. We have developed a prototype of the planning and validation services, by using-as reasoning engines- SWI-Prolog and the SPIN model checker. Such services will be supplied and combined as plug-andplay personalization services in the Personal Reader framework.