So is this cloud sync for my Md files? Who pays for the diffing and versioning?

In a way yes. A hosted llm-wiki, where I handle the diffing, versioning and audit log of what was changed, by what agent and why.

So a git repo + md files?

Yeah, close. But all handled so a user can just focus on connecting the MCP and doing work. Goes to my answer elsewhere here about different between gbrain / llm-wiki… those are highly configurable and powerful, but require technical knowledge and time. I think the vast majority of tech workers will need “that for dummies” ie this just works for them.