I'm starting to think that I completely misunderstood the goal of your plugin.

I understood that it provided a unique identifier for a note, that could be referenced elsewhere. Meaning that I expect it to last the lifetime of the note. Like a SSN for instance.

But when you talk about being tied to Obsidian, I'm not sure I follow. If it's an identifier to an Obsidian note, sure, the ID should be tied to Obsidian. But if it's an identifier to a .md file, then the ID should not be tied to Obsidian.

For the second case, it's not an issue: think about Obsidian as an IDE, and your vault as a GIT repository. You can create your own ID logic, idependant of Obsidian itself, but stored in the vault. Your pluging will implement this logic, and add the necessary requirements to make it work in Obsidian. And you could make a plugin for VSC that would implement the same logic, and adding the requirements to make it work in VSC.

In this case, I would expect the note ID to be the same, weither I access the vault (GIT repo) through Obsidian or VSC.

That's a good point. I'll consider it for the next version.