Evan Winter's The Rage of Dragons

In the Assessed Territories, your worth is a number on a plate — your Birth Class, your Level, your ceiling — and the ceiling for serfs is permanent, by design, filed as temporary in Year 112 and never reviewed. When ledger clerk Vael discovers an exploit that lets her siphon experience from the nobility, she uses it to save her brother from Reassignment. What she builds instead is a network, a romance with the true believer whose identity collapses when the System finally uses her, and a path to the relay nodes buried beneath the city where the System's source code waits — 300 years of pending review, authored by a committee, run on extracted labor, and correctable by anyone with the right Resonance and enough people willing to hold the line.