This documentation article: https://help.kagi.com/kagi/features/bangs.html#supported-bang-syntaxes lists five "assistant bangs":
!fast
, !chat
and !custom
perform standard searches without any discernible effect. !code
performs a search on a site called searchco.de
which times out after about a minute, and !expert
takes me to a Dutch electronics retailer.
I would have expected the assistant bangs to invoke their described respective assistants and receive some kind of output from an AI endpoint.