How would AI respond? Would they figure out where the shot came from and go investigate?
Yes
/thread
If I'm understanding OP correctly, they're talking about the scenario of shooting from stealth and then hiding at the end of your turn, so that the AI doesn't know where you are and just stands there. Not real-time stealthing before a battle, in order to try to get Surprise.
In 5e, when you attack, you
reveal your position. Even if you hide again, the enemies were still alerted to your previous position. Now, if you attack -> hide -> move, you might be safe. But at the very least the enemies should go to your last known location to search you. Alternatively/in addition, the enemies could take the Hide/Dodge actions (if ever implemented) in response to damage.
