1. A method comprising: receiving, by a computing system, an indication of a query received by a first computing device from a user, wherein the query forms at least a part of a conversation between the user and a first assistant executing at the first computing device; determining, by the computing system, whether to handoff the conversation from the first assistant executing at the first computing device to a second assistant executing at a second computing device, wherein determining whether to handoff the conversation is based at least in part on a difference in functional capabilities between the first computing device and the second computing device, and wherein determining whether to handoff the conversation is based at least in part on a difference in functional capabilities between the first computing device and the second computing device comprises: determining, by the computing system, that a response to the query is to be visually outputted, and in response to determining that the first computing device is not operably coupled to a first display device, and that the second computing device is operably coupled to a second display device, determining, by the computing system, to handoff the conversation to the second assistant executing at the second computing device; and in response to determining to handoff the conversation to the second assistant executing at the second computing device, sending, by the computing system to the second computing device, an indication of the conversation.