Associating a semantic service description (SSD) with a service, wherein the SSD comprises a semantic description of the service, including a semantic description of a parameter of the service, according to a computer interpretable language, and, as a service grounding, a mapping between the computer interpretable language expressing the SSD and an interface, including an interface parameter, of the service. A dynamic composition of a task based upon a user selection of a plurality of known services is supported and a dynamic association of the task with a user interface of an application is supported, based upon associating the task with the user selection of a UI object, a UI display screen, and a UI event for the application.