Stop Hand-Rolling
Three months into a production UI I asked whether Svelte would be safe to adopt for the next revision.
Agents hand-roll load-bearing infrastructure because they are optimising the task in front of them, and the task in front of them is always the first version. Instructions bind only the session that reads them; a principle binds the reasoning, so a session that never saw the instruction still lands on the same answer. Maintenance is invisible from there.