When does a player choose to use flash of genius?

[XZlayeD]

the ability states:
Starting at 7th level, you gain the ability to come up with solutions under pressure. When you or another creature you can see within 30 feet of you makes an ability check or a saving throw, you can use your reaction to add your Intelligence modifier to the roll.

You can use this feature a number of times equal to your Intelligence modifier (minimum of once). You regain all expended uses when you finish a long rest.

the text is ambigous as to when the player can decide to use the ability. Is it before the roll entirely? is it after the roll, but before the player knows if they will pass/fail, is it after this point?

As a test my DM and I have decided to have it so flash of genius is used before the roll, and frankly it doesn't feel very good that way.

[Lvl 2 Expert]

Usually when an modification of a skill roll can be used after the roll it will say so, something like "this ability can be used before or after the roll is made, but before the result is announced".

However, the skill system of 5e and dnd in general is not really set up to be overpowered or game breaking. So it might not be a bad thing to allow it used after the roll. Thematically it kind of works as well. You see someone doing something and notice a smarter way to do at, yelling it at them fast enough that they can still change their approach. "Lift with your knees Gronk, not with your back!"

[XZlayeD]

the way we're currently playing it, Flash of Genius is more often than not just wasted on a roll that ends up succeeding without the intervention of the artificer. I Suppose I'm looking for a consensus on if it's too strong to have the power to see the roll before deciding. Dice manipulation and other modifiers such as bardic inspiration, luck and portent all have specific text to make it clear how it is supposed to be used, where the ambiguity makes it hard for us to decide, especially since it costs the artificers reaction, which is already competing with shield and absorb elements.

[MoiMagnus]

My quick google search seems to indicate that:
1) Probably DM's call because unclear in RAW.
2) Since most reactions are chosen to be used after the triggering event, the RAI is probably that you chose after seeing the roll.
3) Some even argue you know if the roll would be a success or a failure since contrary to Bardic Inspiration, it is not explicitly said that it happens before, so it might happen after.

As a DM, I'd go for "you know the roll, and whenever it makes sense, you know if it is a success or a failure (so not for most saving throws, but quite often for skill checks)".

[XZlayeD]

When would you judge for it to make sense?

The ability itself is very wide in its use since it can both be used on ability checks and saving throws, so there's so many instances of it being able to come up.

[Keravath]

If you want a very literal interpretation ...

A character has not actually made an ability check or a saving throw until AFTER they have rolled a die. If you think about it, before rolling a die they are only PLANNING on making an ability check, or they MIGHT have to make a save. As an example, an opposing wizard casts a fireball. Does the character make a dex save? Not necessarily - maybe the fireball is counterspelled. Saving throws or ability checks actually haven't happened until after the die roll is made.

The trigger for for flash of genius is "When you or another creature you can see within 30 feet of you makes an ability check or a saving throw" which doesn't happen until AFTER the die is rolled. So, I would interpret this as meaning the character with flash of genius gets to see the result of the die roll but not whether that roll is successful or not before the ability is triggered since until the die roll is made the target hasn't actually made an ability check or a saving throw.

Another example, the rogue says I am going to pick the lock, the character uses flash of genius, the rogue says wait, I am going to check for traps first ... which ability check does flash of genius apply to? Until the die is rolled an ability check has not occurred and the player can change their mind about their actions. Since reactions require concrete triggers, and the trigger says an ability check or saving throw, then the die roll has to occur and the ability check or saving throw made prior to the flash of genius being used. The only question is whether the character with flash of genius gets to see that die roll and since the check has to made before triggering the ability, I don't really see any reason why the user would not see the die roll.

[Lvl 2 Expert]

Another example, the rogue says I am going to pick the lock, the character uses flash of genius, the rogue says wait, I am going to check for traps first ... which ability check does flash of genius apply to? Picking the lock. The bonus flash of genius gives stems from "the ability to come up with solutions under pressure". It's not a magical motivation bonus to the next roll, it's very situational advice based on acute insight. So you're telling the rogue "the right side of this lock looks more rusted than the left, based on the pattern I think you can break the third pin off with a flick of the wrist, which should make the process easier", that advice does not apply to searching for traps.

[stoutstien]

Picking the lock. The bonus flash of genius gives stems from "the ability to come up with solutions under pressure". It's not a magical motivation bonus to the next roll, it's very situational advice based on acute insight. So you're telling the rogue "the right side of this lock looks more rusted than the left, based on the pattern I think you can break the third pin off with a flick of the wrist, which should make the process easier", that advice does not apply to searching for traps.

I think the example is based on the player saying they want to attempt to pick a lock and then decide otherwise rather than the character. Flash of genius is a reaction based on a character's action not on a player's choice of action.
FoG is definitely murky.

[XZlayeD]

It begs another question though - how does the artificer fair in terms of relative power if either of the methods are used?

[stoutstien]

It begs another question though - how does the artificer fair in terms of relative power if either of the methods are used?

it really depends if a individual DM is being consistent with his style of ruling across the board and not singling out one particular feature or ability.

Regardless of how table runs it static bonuses like it are rare.

[OnceIWasABard]

It begs another question though - how does the artificer fair in terms of relative power if either of the methods are used?

They'd certainly be better if you could turn certain fails into certain passes. At the very least, it'd produce less wasted uses.
I'd rule it could be used at any point, mostly because I like the idea of, for example, another character failing to translate a book of runes/glyphs and your 'genius' is just pointing out they're holding it upside-down.

[Lvl 2 Expert]

I think the example is based on the player saying they want to attempt to pick a lock and then decide otherwise rather than the character. Flash of genius is a reaction based on a character's action not on a player's choice of action.
FoG is definitely murky.

But the person using the Flash of Inspiration ability still used it in reaction to them picking the lock. The fact that the second player withdrew that action may withdraw the Flash of Inspiration as well, but it definitely per RAW does not give person 2 free reign to invest that Flash of inspiration in a different skill check instead. Because as per the description it applies to a specific check, not to any random check, as it is specific advice based on a specific situation that's unfolding.

[stoutstien]

But the person using the Flash of Inspiration ability still used it in reaction to them picking the lock. The fact that the second player withdrew that action may withdraw the Flash of Inspiration as well, but it definitely per RAW does not give person 2 free reign to invest that Flash of inspiration in a different skill check instead. Because as per the description it applies to a specific check, not to any random check, as it is specific advice based on a specific situation that's unfolding.

The point was that they couldn't use FoG to Begin with because the conditions to use it haven't taken place.

[MaxWilson]

If you want a very literal interpretation ...

A character has not actually made an ability check or a saving throw until AFTER they have rolled a die. If you think about it, before rolling a die they are only PLANNING on making an ability check, or they MIGHT have to make a save. As an example, an opposing wizard casts a fireball. Does the character make a dex save? Not necessarily - maybe the fireball is counterspelled. Saving throws or ability checks actually haven't happened until after the die roll is made.

If this were true, Portent would be impossible to use, since you have to declare it before the roll happens.