Is there a way to force a tag into a topic in a specific category without the user having to add it?

[pfaffman (Jay Pfaffman)]

@MikeNolan

That would work for my specific use case, but I’m trying to think ahead here towards a plug-in that would have more general value

The General Problem

That’s not quite the one I was looking for, but I think that you’ll be better off solving your actual problem than ones that you imagine.

@MikeNolan

I want this post to have separate special formatting

That one will be tough, though you could make a plugin that added a PostCustomField and added it to the serializer.

Just deciding that you’ll have categories that contain only recipes/need special formatting pretty much solves the vast majority of use cases. Enforcing a set of tags is another way that’s a bit more fussy, but also involves virtually no code to maintain.