In one embodiment, a method includes establishing a video call between a plurality of client systems, wherein access to an assistant system is persistently maintained during the video call, receiving, from a first client system of the plurality of client systems, a request by a first user to be performed by the assistant system during the video call, wherein the request references one or more activities associated with one or more users associated with the plurality of client systems, analyzing, by a context engine of the assistant system, images of a scene of the video call to identify the one or more activities within the scene, instructing the assistant system to execute the request based on the identified one or more activities, and sending, to one or more of the plurality of client systems, a response to the request while maintaining the video call between the plurality of client systems.