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 a 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.