You recognize details about traps by sight. For a given trap, you know the following.
- How lethal it is.
- If it sets off some effect when disarmed.
- What it was built for (keeping people out, part of a puzzle, and so on).
- How lethal it is (roughly).
- If it's designed to trigger once, a handful of times, or many times.
- Any noteworthy features of of the trap.
You may also make an investigator check to learn more about the trap, its purpose, its construction, or other details the GM allows.
At GM discretion, you can also spend 10 minutes studying a trap up close to get additional information.