That's a great question! @joseluizferreira's solution is the best we have right now, I think! I am actually in the process of working on some better interactive tag tooling to play with 
So hopefully more to come there soon!
If you have feedback on what you're looking for or a proposed interface, I'd be curious to hear your thoughts on this thread! Updating tags programatically - #11 by tbradley
I'm currently imagining an interface like:
tags <- get_tags(client)
set_content_tag(content, tags$Section$tag$subtag)
get_content_tags(content)