In recent years smart mobile devices have bolstered new interaction scenarios that require more sophisticated human-machine interfaces. The leading developers of operating systems for these devices now provide APIs (Application Programming Interface) for developers to implement their own applications, including different solutions for developing graphical interfaces, control sensors and providing oral interaction. Despite the usefulness of these resources, defined strategies are still needed for developing multimodal interfaces to take greater advantage of these devices for identifying and meeting the needs of users. Currently, these applications are typically ad-hoc and facilitate oral communication only through simple commands. In this paper we propose the practical application of context-sensitive multimodal conversational agents to provide advanced library services that dynamically consider specific user needs and preferences, as well as the specific characteristics of the environment in which the interaction occurs. Such agents would improve and customize the service provided by a mobile device with Internet access. Our proposal integrates features of Android APIs on a modular architecture emphasizing the management of interactions and context awareness in order to create robust applications that can be easily updated and adapted to the user.