But let's pretend you were playing with us. If you said "I use Perception" at our table, the DM would not be rude. They'd ask you to be more specific based on what was just described in the fiction. They'd want you to interact with the fictional scene - what is your character trying to accomplish and how are they going about it - not just use a standard action of "Perception". So, if the DM just described a room with a rug, a tapestry, a desk, and a door, the party might split up to check out each of those things. Perhaps your character would do something like: "I want a closer look at the rug. I'm going to try to lift up an edge with my sword to see if there's anything under it." Once the other players had a chance to chime in with what their characters were doing in the scene, the DM would resolve each action.