1. A computer-implemented method comprising: receiving, by a voice action system, data defining a new voice action that does not currently exist for a software application installed on one or more devices, the software application being different from said voice action system, the data indicating one or more operations for the software application to perform the new voice action and one or more trigger terms for triggering the new voice action; generating, by the voice action system, a voice action passive data structure based at least on the data defining the new voice action, wherein the voice action passive data structure comprises data that, when received by the software application, causes the software application to perform the one or more operations to perform the new voice action; associating, by the voice action system, the voice action passive data structure with the one or more trigger terms for triggering the new voice action; receiving, by the voice action system, a user command utterance obtained by a user device, the user device having the software application installed; determining, by the voice action system, that a transcription of the user command utterance corresponds to the one or more trigger terms associated with the voice action passive data structure; and in response to the determination, providing, by the voice action system, the voice action passive data structure to the user device which is remote from the voice action system, thereby causing the software application installed on the user device to perform the one or more operations to perform the new voice action.