PERCEPTION ROLLS?
Well ... we don't use them. They come from questions like, "Do I see the person who stole my XYZ?" Or, "Do I see the hidden monster?" Or, "Can I combine my perception stat with my find traps stat?" Or, "Do I find a shop that sells XYZ in the city?" Or, "Do I hear anything as I lay silently listening in this forest?"
We think anything you may want to achieve with a perception roll can be accomplished through descriptive explanations, discussions about the situation, and, perhaps creative skill use and card combinations in hands (that should be described in this game). Most of the time, just telling the player the answer/what-they-want-to-know is more than adequate. A player says, “I scan the market looking for the thief.” Instead of a perception roll consider this alternative. If the thief is actively avoiding being found, then they must be using a Hand (probably containing Stealth), otherwise they will easily be seen. To find one using Stealth, a character needs to have a counter-Skill (Observe). If a player doesn’t, they don’t find the thief because their training doesn't include finding those that are actively using their own Skill. All of those outcomes are excellent fodder for dialogue and creative descriptions. And they are used to advance the story.
The question I ask is, "Does a perception roll serve the story?" For me, it almost never does as the story is served in a more satisfying way through roleplaying and descriptions of the scene and action. Perception rolls yield success or failure, along with an increasing chance of success as the characters gains in levels and abilities. But as the GM involved in story creation, if your thief is avoiding detection, why have you made that choice? It’s up to you to decide if now is the time for the thief to be found. Then say, “You scan the market, everything looks … wait … there is someone that looks like your culprit toward the back of the market at a cabbage cart.” Ask yourself the question, “What happens to the story if the player fails their roll?” If you need success to move the story forward, you could give the information based on the descriptions, discussions, and skill use.