There is quite a lot of good advice here, however with one caveat. Documents require constant maintenance, and a "living" document that several people can edit is probably contradictory to the "always stay accurate" principle. Not everyone shares the same mental model of the project and sometimes things change but not everyone knows at once.

You can choose an accurate document that doesn't change often, or an accurate-ish "dynamic" document that is managed by a single entity, or a document editable by more people. You can't have a perfectly accurate document that's also changing constantly and is managed by multiple parties.

As a side note, thank you for not coming up with silly acronyms for everything.