This is inspired by the recent question: "Can I use the Enchantment wizard's Instinctive Charm feature after seeing the die roll?" where this is mentioned at the end, but to avoid having multiple things going on there at once I thought it would be a good idea to ask this separately.
There are a few features in the game that occur "after seeing the roll, but before knowing whether it hits or misses", (or at similar times):
Valor Bard's Combat Inspiration:
[...] When an attack roll is made against the creature, it can use its reaction to roll the Bardic Inspiration die and add the number rolled to its AC against that attack, after seeing the roll but before knowing whether it hits or misses [...]
Enchantment Wizard's Instinctive Charm:
[...] When a creature you can see within 30 feet of you makes an attack roll against you, you can use your reaction to divert the attack, provided that another creature is within the attack's range. The attacker must make a Wisdom saving throw against your wizard spell save DC. On a failed save, the attacker must target the creature that is closest to it, not including you or itself. If multiple creatures are closest, the attacker chooses which one to target. On a successful save, you can't use this feature on the attacker again until you finish a long rest.
You must choose to use this feature before knowing whether the attack hits or misses [...]
Bard's Cutting Words:
[...] You learn how to use your wit to distract, confuse, and otherwise sap the confidence and competence of others. When a creature that you can see within 60 feet of you makes an attack roll, an ability check, or a damage roll, you can use your reaction to expend one of your uses of Bardic Inspiration, rolling a Bardic Inspiration die and subtracting the number rolled from the creature’s roll. You can choose to use this feature after the creature makes its roll, but before the DM determines whether the attack roll or ability check succeeds or fails, or before the creature deals its damage.
Conquest Paladin's Guided Strike:
You can use your Channel Divinity to strike with supernatural accuracy. When you make an attack roll, you can use your Channel Divinity to gain a +10 bonus to the roll. You make this choice after you see the roll, but before the DM says whether the attack hits or misses.
I would like answers here to assume that the player is told the actual number that appears on the die, this is supported in the in the following Q/A:
- Does Combat Inspiration require the GM to announce attack roll totals?
- How much does a bard know when they decide to use Cutting Words?
What I'm wondering is when using a feature like Combat Inspiration, what happens when the GM announces that the roll was a 1, or a 20? Does this mean you "know whether it hit or missed" and thus can't use the feature?