Breadcrumbs for Humans and AI: How Pattern Docs Guide Developers to Correct Code

A backend returns 200 OK with a JSON error body when downloads fail. This may seem unexpected at first. 200 indicates success. Arguably this is a protocol adherence issue, but it remains. Every new developer that works on downloads must learn this—one way or another. Every code review catches someone checking response.ok. The knowledge exists—in some developers’ heads.