All Systems Red is a first person narration by a "Murderbot," which is the narrator's term for itself and its fellow security robots. SecUnits are a mix of combat robotics with cloned human parts that make it more of a cyborg than a robot, although the term is never used. The narrator is unique in that it has managed to hack its governor unit, giving it the ability to disregard orders, an ability that it keeps a careful secret because its discovery would likely lead to a complete mind wipe or even destruction.
The story has gotten a lot of praise and won some genre awards, which I found a bit surprising at first because the tone of the story is actually rather old fashion SF. There is nothing about the plot or narration that would seem out of place in an old issue of Astounding Science Fiction from the John W. Campbell days. In that though is the secret of the story's subtle brilliance.
The narrator is a sentient being that wants to do its job with as little human interaction as possible. The bot is not an emotionless logical cliche, it has a full range of emotions with the exception of anything related to sexuality as it is asexual by design. The bot is capable of anxiety, annoyance, and protectiveness; if anything it comes across a bit tsundere. High functioning Asperger's was the term that kept popping into my head while reading it. Which brings me back to the connection to old school SF.
A lot of older Science Fiction from the era of the pulp magazines reads like it was written by and for high functioning Asperger's cases. The focus is on setting and problem solving, not on character development or interpersonal relationships. The characters display limited emotional range and any romantic elements are strictly background and never central to the plot. I think this is why to this day SF is often dismissed by critics and scholars as boy's literature with limited appeal for women. Of course this stereotype was never really true and is even less so today when there are many successfully women SF authors. I may be reading something into the text that the author did not intend, but it seems to be that Martha Wells is looking back at old school SF and adding a bit of psychological subtext to its cerebral focus.
There is also another level you can take this to and that is that Murderbot is essentially a slave. No matter how kindly or benevolent its "clients" are they are still buying and selling it for its capacity to work. Legally it is inventory and even if its owners are friendly they are still its owners. Murderbot rejects overtures of friendship because the only way it can be free is through escape, either through mental isolation or physical separation.