How do I know if my codebase is already drifting?
Three practical signals: you find two pieces of code doing the same job, you cannot confidently say which parts call which, or you avoid changing certain files. Any one of them means the map in your head has stopped matching the code.
From Why AI-generated apps fall apart in week three, published 9 August 2026. That article is where the reasoning behind this answer is set out, including what it does not cover.