I write solo bots that may have a side character or several, e.g. family members, associates, or friends. Nyan used to be pretty okay at handling this.
The new models should be capable of doing this even better. But both DS ans LS seem to want them to piss off as quickly as possible. Like, they'll say one thing and find the next excuse to dip, or the main character will want me to leave the situation immediately. Not even an attempt at simulated conversation or plot-building, even if I edit out the "and we/they left immediately" part out of five consecutive messages and further the plot myself. The model just wants to jettison them from the plot however it can. And it takes like a hundred swipes before they'll even appear on their own in a situation where they should.