In one embodiment, a method includes by a client system associated with a user, receiving, at the client system associated with the user, a user input, parsing the user input to identify an n-gram associated with a wake word from a plurality of wake words corresponding to a plurality of assistant systems associated with the client system, wherein each assistant system provides a particular set of functions, determining that the wake word corresponds to a first assistant system of the plurality of assistant systems, wherein the first assistant system provides a first set of functions, sending, to the first assistant system, a request to set an assistant xbot of the first assistant system into a listening mode, and receiving, from the first assistant system, an indication that the assistant xbot is in listening mode responsive to a determination that the user has permission to access the first assistant system.