Jugofthat said:
...Wait. What exactly is this about? Are you saying I'm not allowed to add an artist's or commissioner's info (from a source) to a post if I'm not its uploader?

Unless "to create information" (that seems pretty vaguely worded) means I'd have to be deliberately pulling things from my ass and making it seem as though it's quoting one of the people involved. Now outlawing that I could understand.

The second part is correct, if you wish to edit the description to match the description on the original upload you're more than welcome to do so. The thing we forbid is writing made up crap to hope and influence the tags or other such nonsense.
If you do edit descriptions be mindful if the uploader is either the artist or the commissioner, you should let them deal with their descriptions in those cases.