I've noticed some of the tag wiki entries are only very basic one-line definitions, while others go into some detail and provide examples of the topic.
I personally do think that a little extra detail is nice for those looking to understand one of the tags, but how authoritative does that description need to be (does it need sources)? And how long should the description be? At some point, just going to the corresponding Wikipedia article would probably be a better idea for the reader. And for the editor, editing the corresponding Wikipedia article would probably be more helpful to the world.
Are there any guidelines or good examples for a good tag wiki entry?