A prompt is text. A skill is behavior. That distinction sounds academic until you try to hand your work to someone else. I have used skills 20+ times a day since December. I am now running 25 of them against 75 tests, and the tests are the part nobody talks about. Here is why they exist. I had an exec update skill that kept burying the bad news. One run described a Stripe bug that was corrupting an activation denominator, and filed it under wins, because technically the number went up. A…