Perhaps useful agents don't have to be very complex language- understanding -and-speaking things. In Computers as Theater, Laurel refers to a system that didn't understand language but was programmed to understand tone - and that successfully answered people's inquiries based on that capability.

An agent is something that has agency - by which we really mean it has a mind of its own.

"Can computers think? There is an easy answer. Computer-based agents ... do not have to think ....; they simply have to provide a representation from which thought may be inferred." 6

I click on a folder, it opens, I think the computer understood me.

"At the grossest level, people simply attribute agency to the computer itself." 7 .... and to their cars, and refridgerators and toys.

Laurel speaks about the "traits" that an agent needs:-
"There are two kinds of traits; traits that determine how an agent can act (internal traits) and traits that represent those internal predispositions (external traits.) People must be given clues be the external representation of an agent that allow them to infer its internal traits." 8

If the external and internal traits are out-of-kilter it can be annoying. Like-wise if the agents traits arbitrarily change. On the other hand, context should affect the agents response as in the interactive mother.