Ok so by taking this feat would you use your casting modifier when determining the effects?

Example 

Careful Spell

When you cast a spell that forces other creatures to make a saving throw, you can protect some of those creatures from the spell’s full force. To do so, you spend 1 sorcery point and choose a number of those creatures up to your Charisma modifier (minimum of one creature). A chosen creature automatically succeeds on its saving throw against the spell.

Using Charisma as a Wizard does not make much sense as your scores are going Int, Con, Wis the reset are dump that is what magic is for.  

The feat doesn't say it does, so it doesn't.

Oof. 

Quote from D20tavernaz >>

Ok so by taking this feat would you use your casting modifier when determining the effects?

 

Example 

Careful Spell

When you cast a spell that forces other creatures to make a saving throw, you can protect some of those creatures from the spell’s full force. To do so, you spend 1 sorcery point and choose a number of those creatures up to your Charisma modifier (minimum of one creature). A chosen creature automatically succeeds on its saving throw against the spell.

 

Using Charisma as a Wizard does not make much sense as your scores are going Int, Con, Wis the reset are dump that is what magic is for.  

 Remember, metamagic is usually the calling card of a Sorcerer, which is a Charisma based class.  it makes since that the feat would also use Charisma...

Anyway, an Evocation Wizard gets a similar (and better) effect with its Sculpt Spell ability.

Then I ask why make this available to casters. 

this is a throwback/nod to 3.5 dnd where wizards have access to meta magic feats. Where you could get things like widen spell, extend spell and so on. 

in the book that seems to be 100% about customization. It does not makes sense that it would be left to CHR sorc. 

if so then this is solely restricted to bars, sorcs, warlock. I don’t think that this makes sense at all. 

Only 2 of the sorcerer's 10 metamagic options scale off CHA and any class can have decent CHA so it really isn't a big deal. If you dumped that ability, pick 1 of the other 8 metmagics (that are better anyway).

TCoE is still very much about customization, but it is not about making every character only need 1 ability to do everything.

Great point! 

Well, Martial Adept still uses Strength or Dex, like the original Battlemaster, so that’s a point in favor of it being intended (maybe). But I don’t see any Eldritch Adept choices that key off of CHA, the few eligible that give you spells make no mention of a preferred casting modifier, nor does the Eldritch Invocation introduction do so. So presumably, Eldritch Adept matches your spellcasting class, Martial Adept gives you your choice of two stats, and only Metamagic Adept is locked to a single stat.

Debatable whether that’s intended, but not the end of the world to enforce RAW.

This is my point. 

So maybe this is a discussion to have with the dungeon master. 

You need sorcery points to power the feat, so you presumably already have levels in sorcery; and I'd assume you had a decent CHA in order to ensure that your sorcery spells actually have decent DCs.

The dirty secret of Metamagic Adept is that while it is dressed as a "you can dip into what sorcerer can do!" feat, it's actually better for sorcerers than any other class.

Magic Initiate still has the stat key off the class you pick. That already should of set the precedent that features from classes (Spellcasting for MI, Metamagic for MA) that use a certain stat don't just automatically change when they are a part of a feat.

Quote from 4yulming4 >>

Magic Initiate still has the stat key off the class you pick. That already should of set the precedent that features from classes (Spellcasting for MI, Metamagic for MA) that use a certain stat don't just automatically change when they are a part of a feat.

Magic Initiate explicitly tells you to do so. The fact that Eldritch Adept does not, if anything, suggests that you do not follow Magic Initiate's precedent in that regard. '

Quote from Farling >>

You need sorcery points to power the feat, so you presumably already have levels in sorcery; and I'd assume you had a decent CHA in order to ensure that your sorcery spells actually have decent DCs.

 The feat gives you 2 sorcery points to play with, so I don't know that it presumes you're a Sorcerer or MC Sorcerer when you take it. 

You know- now that you mention it. If you take Eldritch Adept with the Thief of Five Fates invocation and cast Bane- wait no you need a warlock spell slot for that one...

If you take Eldritch Adept with the Mask of Many Faces invocation, what do you use for the Saving Throw DC? Since Disguise Self technically has a Saving Throw DC,

"To discern that you are disguised, a creature can use its action to inspect your appearance and must succeed on an Intelligence (Investigation) check against your spell save DC."

I guess I see your point Chicken_Champ. Eldritch Adept does indeed require you to have the spellcasting or Pact Magic feature probably for this very reason.

That would suggest you use the Saving Throw DC of whatever class you have spellcasting from- except if your a non-warlock, you can't because (using wizard as a example) it states that "you use your Intelligence modifier when setting the saving throw DC for a wizard spell you cast and when making an attack roll with one."

Edit: TIL if you want to skip a ASI for whatever reason, be a non-warlock and take Eldritch Adept (Thief of Five Fates). I'm going to pull up my twitter account from 50 years ago and tweet Jeremy Crawford I need answers.

Edit from a couple hours later: Yeah I can totally see what Chicken_Champ is saying. I'm going to wait to see if Jeremy Crawford actually answers my tweet before posting again, since it can honestly go either way. I know Jeremy isn't the best but better than nothing, maybe bringing this up to his attention will result in a errata or sage advice. Who knows?

I don't think there's a "right" answer to edge cases like that, because 5E lacks a catch-all rule about choosing a default ability modifier. I can imagine a world where Constitution is used as your default ability modifier whenever you pick up an ability somehow that requires a modifier but doesn't describe what ability score sets it. Or, which provides explicitly that you may choose an ability score of your choice in such rare edge cases. Or, which states explicitly that you don't have a modifier whenever you pick up an orphaned ability, and have to use a +0. 

But lacking that, a DM will always ultimately be asked to make a judgment call: is it more reasonable to require the wizard to use Charisma for his Mask of Many Faces cast of Disguise Self, because the invocation originally comes from a CHA-based Warlock's ability list, or to allow the Wizard to use Intelligence, because they picked up the feat as a result of a Wizard level, have an Intelligence-based spellcasting ability that they're built around, (and hell Disguise Self is actually "a Wizard spell" no matter how you learn it, to rehash that old argument :p)

My original point that I want to make is this feels like the writers left this out. 

These feats like this truly feel like they are meant for classes to dip into another class without multiclassing. Encouraging the player to stay in class vs going outside of the class. The intent is there. RAW here could be an editing issue or simply a discussion for the table. 

It allows for a different flair to the class without having to multiclass. Which is great for the game. 

Quote from 4yulming4 >>

You know- now that you mention it. If you take Eldritch Adept with the Thief of Five Fates invocation and cast Bane- wait no you need a warlock spell slot for that one...

If you take Eldritch Adept with the Mask of Many Faces invocation, what do you use for the Saving Throw DC? Since Disguise Self technically has a Saving Throw DC,

"To discern that you are disguised, a creature can use its action to inspect your appearance and must succeed on an Intelligence (Investigation) check against your spell save DC."

I guess I see your point Chicken_Champ. Eldritch Adept does indeed require you to have the spellcasting or Pact Magic feature probably for this very reason.

That would suggest you use the Saving Throw DC of whatever class you have spellcasting from- except if your a non-warlock, you can't because (using wizard as a example) it states that "you use your Intelligence modifier when setting the saving throw DC for a wizard spell you cast and when making an attack roll with one."

Edit: TIL if you want to skip a ASI for whatever reason, be a non-warlock and take Eldritch Adept (Thief of Five Fates). I'm going to pull up my twitter account from 50 years ago and tweet Jeremy Crawford I need answers.

Edit from a couple hours later: Yeah I can totally see what Chicken_Champ is saying. I'm going to wait to see if Jeremy Crawford actually answers my tweet before posting again, since it can honestly go either way. I know Jeremy isn't the best but better than nothing, maybe bringing this up to his attention will result in a errata or sage advice. Who knows?

Quote from Chicken_Champ >>

I don't think there's a "right" answer to edge cases like that, because 5E lacks a catch-all rule about choosing a default ability modifier. I can imagine a world where Constitution is used as your default ability modifier whenever you pick up an ability somehow that requires a modifier but doesn't describe what ability score sets it. Or, which provides explicitly that you may choose an ability score of your choice in such rare edge cases. Or, which states explicitly that you don't have a modifier whenever you pick up an orphaned ability, and have to use a +0. 

But lacking that, a DM will always ultimately be asked to make a judgment call: is it more reasonable to require the wizard to use Charisma for his Mask of Many Faces cast of Disguise Self, because the invocation originally comes from a CHA-based Warlock's ability list, or to allow the Wizard to use Intelligence, because they picked up the feat as a result of a Wizard level, have an Intelligence-based spellcasting ability that they're built around, (and hell Disguise Self is actually "a Wizard spell" no matter how you learn it, to rehash that old argument :p)

What would a Wizard/Bard/Cleric multiclass character use as their DC if they picked up Eldritch Adept with Mask of Many Faces?  INT, because Disguise Self can be a Wizard spell? CHA, because it can be a Bard spell? WIS, because they picked the Feat with their ASI from a Cleric level?  CHA, because it's meant to be used as a Warlock?

I think this needs an erratum. :D

Feats are not as difficult to attribute to a class as they get made out to be. There is a single clear and correct answer to what class the Eldritch Adept feat belongs to for a Wizard 4/Cleric 3/Bard 3: the Wizard. An ASI/Feat isn’t a function of character level, it’s a class feature, which appears on the classes’ progression table and in its features.