A UI Opinion:
If your app has a tag-centric capability, the default token, i.e. w/o marker characters, should be the tag, not the string literal. The string literal should require quotation marks.
To search for tagged [GeePaw] books that are not tagged [read], I should be able to type:
geepaw and not read
In Calibre, I am required to type:
tags:"=GeePaw" not tags:="read"
To quote my late father, "That really gripes my ass."
@GeePawHill This makes no sense to me. I don't understand the difference in meaning between :"=word" and :="word" and it hurt my head trying to figure it out.