In most cases, I work out the story fairly comprehensively, giving
the writer a beginning/middle/end, and some of the characters. In a few
cases, it's less than that, a general direction and items which have to
happen in that episode. Very often it's in writing from me, ranging from
a paragraph or two to a few pages.
Generally, in TV, this would mean that I would take shared story
credit on the episode. But there are no arbitrated credits on B5; the
freelancer gets all the credit, and all the residuals, and rightly so.