Oh, this story made me so mad. In a good way. I felt really bad for her. I think it's pretty likely that she is leaning toward the autistic side of the spectrum and her dad has decided he's going to use his money and influence to fix her brain that he considers defective. Rather than talking to her, trying to understand how she interacts with the world, and trying to help find a place in the world she's comfortable in. Of course that latter would be a lot of work, so he just throws money at the problem and then walks away, as he is apparently accustomed to doing, wiping his hands clean of the "problem" as "solved". Ugh.
I think that anyone who had social issues with high school can relate to this on some level (and no wonder, because most of high school consists of the most socially toxic sludge that one can imagine), but people with autism most of all. What we all wouldn't have given to have something to just make everything go okay, to not be horrible, to help us make friends and find someone to date. And turning us all into frustrated psychologically damaged puppets as a result. Something like this critter would be hard to get rid of because it's a social drug. Stop using it, big time withdrawal, friends lost and anxiety increased, keep using it and even if there are clearly bad consequences you can't see those consequences clearly through the euphoria of finally getting that social prowess you have always deserved. ( I have not been diagnosed as autistic, but judging by the markers I'm kindof straddling the line)
My guess is that this thing will never get mass-marketed, because it's going to completely break down when it has to compete against other critter-bots with similar capabilities. They're going to be playing tug of war with each other with their human hosts as the rope, and some poor kids going to snap and maybe murder somebody or commit suicide from the constant psychological strain. Maybe they'll predict that while they're still prototyping and no one will really get hurt, but if they actually released this I think people would start dying and it would get recalled.
Regarding the ending:
I'm really quite surprised that multiple people have thought that the ending was tidy or happy. The main arc of the story consisted of her coming to the realization that she didn't like the person this tool had made her become, someone who she really wasn't--that realization is certainly happy, self-understanding is a powerful thing. But what does she do? She decides that, because it made her into someone she didn't like, she would coerce it into making her into someone else completely different. Someone who she really isn't.
Theoretically, maybe, this attempt at programming will result in her being comfortable in her own skin and able to interact with her peers in positive and healthy ways. I don't really think that's going to happen though. Certain parts of the critter must be hardwired at a level she can't touch with simple spoken instructions. And she's no programmer, so who's to say her instructions are going to be the ones to get her what she wants? Computers always do what their instructions say, even if that's not what the programmer intended--and unintended consequences and bugs and things take up a lot of a programmers time trying to sort out. Why would someone without debugging experience, whose life is being directly altered by the program in question, have any better luck? I can't help but feel this is going to go horribly horribly wrong in some entirely different way. Maybe next time she'll be able to pull out of the spiral again, maybe next time she'll realize this is a bad idea and smash the thing with a hammer, maybe next time and the time after that she'll iterate closer to a desirable outcome (I think that's unlikely as she's basically trying to optimize the solution to a problem she doesn't understand without understanding the mechanics of the system entirely).
So, yeah, my vote is that the ending is not tidy, and not happy. Not bleak, exactly, because her doom may yet be avoidable, but very dark nonetheless as long as she pursues a route of self-reprogramming.
Not complaining about the ending. It's internally consistent, thematically appropriate, and compelling. I just don't think it's happy or tidy.