Timeline for Can you ready an action to attack a hidden creature before it attacks you?

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Feb 28, 2017 at 19:52	comment	added	Clearly Toughpick		Yes, but the original question makes no mention of heavy obscurement; it doesn't even mention light obscurement, so in that circumstance, when the attacker takes its shot, it reveals itself to the creature. Also, giving away your location means you are disovered, and it means you are no longer hidden.
Feb 27, 2017 at 15:42	comment	added	Szega		@ClearlyToughpick The rules only say that he gives away his location. Not that he is automatically discovered. Think of a creature with darksight firing from a dark room at a creature without darksight. To fire blindly, you need to 1) guess location 2) attack at disadvantage. Only the first one is automatically lifted if you make an attack.
Feb 27, 2017 at 15:26	comment	added	Clearly Toughpick		In your penultimate paragraph, I would rule that the readied action is to attack a seen target rather than an unseen one. This is because the attack's hitting or missing is part of the attack, and at that point the attacker reveals his location - before he can move back into cover. Because the attacker had to have line of sight to make the attack in the first place, a creature with a readied action will also have line of sight back to him when the attack is resolved. So they can see the attacker when he attacks and don't suffer disadvantage for it.
Feb 27, 2017 at 13:10	history	answered	Szega	CC BY-SA 3.0