When AI writes the code, who remembers WHY?

I've been a CTO long enough to have onboarded dozens of developers across teams of varying maturity. The pattern that works has never changed: a new developer reads existing documentation, explores the repository, implements small tasks - often ones designed by a senior to expose how the system's key features work. How is the API structured? Where does state live? How do data flows connect? The developer learns by doing, making mistakes, and reflecting on what went wrong. AI hasn't killed that process. But poorly thought-through adoption of AI has made it much harder for developers to learn a project and the logic behind it. When a developer delegates everything to an AI assistant without reflection and when AI implements the onboarding task, the developer just submits the PR - the task got done, but the onboarding didn't happen. The developer no longer learns from mistakes or learns by discovery, because there were no mistakes to learn from and nothing to discover. That's not an AI pr