Many modern systems and applications are capable of analising the contexts of use in real time, identifying key information to anticipate upcoming actions and optimize their interfaces. Those systems that work in a contextual manner and, usually, in a proactive way, belong to the Context Aware Computing area. The Google App for Android and iOS devices has a virtual assistant service that collects data obtained from different sources associated to the user account and links them to data from the user device. The assistant can identify habits, anticipate probable needs and offer information cards even before the user asks for them. Being part of the Context Aware Computing field, the Google App was elected as study object and was evaluated under the Semiotics Engineering bias. From the application s interface, the quality of the user-designer communication was analysed so, not only the virtual assistant efficiency could be evaluated, but also the user autonomy and the application flexibility according to his needs.