I actually really liked this. I usually don't usually like the Carbon fibre/West world/Black mirror takes on AI. Mostly because I keep coming back to "they have no soul, so why should I care?" question. Brianna is written very well. The setting is established almost immediately with no fuss or hassle. The reason I like Brianna is her questioning. She actually asks some interesting questions that give rise to what it means to "be real" or indeed sentient. I find that really interesting and the twist that maybe the Christopher himself is not "real". "How would he know?" is really good.
Read the story now
I like to think that it is a double-bluff and Brianna has actually replaced the real Christopher. For me that makes the story more sinister and dark, which "excites my palate" for the rest of the stories.
For this one I give a thumbs up and its rare that I get past the first couple of paragraphs of a short story because they don't grip me. This one did and for that I give 5 "jolly good shows" or stars as the case may be here.