This matches my experience building a Go framework with AI as the primary developer. I ended up with a formal Amendment protocol — every architectural change is proposed, consequence-analysed, and approved before implementation. The document that records these decisions (DECISIONS.md) became the most important file in the repo. Not the code — the decisions behind the code.

Versioning the investigation is exactly right. The AI has no memory between sessions. The only continuity is what you write down.