An example method includes receiving, by a computational assistant executing at one or more processors, a representation of an utterance spoken at a computing device; selecting, based on the utterance, an agent from a plurality of agents, wherein the plurality of agents includes one or more first party agents and a plurality of third-party agents; responsive to determining that the selected agent comprises a first party agent, selecting a reserved voice from a plurality of voices; and outputting synthesized audio data using the selected voice to satisfy the utterance.