A review by fishky
The Expert System's Brother by Adrian Tchaikovsky

2.0

Fantasy world that is actually a future world where humans bioengineered themselves to survive on a hostile planet and "ghosts" take over people's bodies in various communities to turn them into subject matter experts (lawmakers, doctors, probably something else) and if you get exiled it excises your implants or whatever and you can't eat anything and you die. The MC gets accidentally exiled and sets off to find a life where you don't need implants to live. Seems unlikely! And also like a bad idea! That's where the book ends, though!