Why does AI keep breaking my existing code?
Because each change is made from a fresh reading of the codebase by a model with no memory of previous decisions and no map of what depends on what. It edits the file in front of it; the consequences land in features that share code with that file. The failure is structural. Better models make the guess better, but nothing in the codebase records the intent they would need to stop guessing.
From Why AI keeps breaking features that already worked, published 20 August 2026. That article is where the reasoning behind this answer is set out, including what it does not cover.