1. A computing device comprising: a processing unit; memory; and one or more microphones; the computing device configured with a speech-controlled digital personal assistant, the operations comprising: receiving speech input generated by a user via the one or more microphones; performing speech recognition using the speech input to determine a spoken command, wherein the spoken command comprises a request to perform a task of a third-party application, and wherein the task is identified using a data structure that defines tasks of third-party applications invokable by spoken command; determining whether the task of the third-party application is capable of being headlessly executed; causing the third-party application to execute as a background process to headlessly execute the task when it is determined that the task of the third-party application is capable of being headlessly executed; receiving a response from the third-party application indicating a state associated with the task; and providing, by a user interface of the speech-controlled digital personal assistant, a response to the user based on the received state associated with the task so that the response comes from within a context of user interface of the speech-controlled digital personal assistant without surfacing the user interface of the third-party application.