Does innate spellcasting stay or go on the sidekick?

[TyGuy]

The spellcaster sidekick instructs the following for the spellcasting feature:

If the creature already has the Spellcasting trait, this feature replaces that trait.
In the case of the innate spellcasting trait, does it stay or go? I.e., is the feature being specific (spellcasting =/= innate spellcasting) or general (innate spellcasting is still a version of spellcasting)?
Thanks in advance.

[Psyren]

They appear to be different traits per MM 10 (and therefore you wouldn't replace IS), but there may be a ruling on this elsewhere I've missed.

[Zhorn]

They appear to be different traits per MM 10 (and therefore you wouldn't replace IS)
Yup, Psyren got it covered here.
Different name = different trait
even if it is a similar name, it's still not a match and is treated as such.
Like how Multiattack and the Extra Attack are not the same thing.

[Chronos]

For comparison, a number of PCs have both spellcasting and inherent spellcasting, and just have both.

[Unoriginal]

The spellcaster sidekick instructs the following for the spellcasting feature:

In the case of the innate spellcasting trait, does it stay or go? I.e., is the feature being specific (spellcasting =/= innate spellcasting) or general (innate spellcasting is still a version of spellcasting)?
Thanks in advance.

Innate Spellcasting and Spellcasting are separate features, so Innate Spellcasting isn't affected by something affecting specifically Spellcasting.

[EggKookoo]

Like how Multiattack and the Extra Attack are not the same thing.

At the same time, I believe the sidekick rules say a creature can benefit from Multiattack or Extra Attack but not both. So it's up to you if the spellcasting thing is intended or an oversight.

[Warder]

At the same time, I believe the sidekick rules say a creature can benefit from Multiattack or Extra Attack but not both. So it's up to you if the spellcasting thing is intended or an oversight.

Well, that's because Extra Attack adds onto the Attack action, and Multiattack is its own action and separate from the Attack action - the two features don't interact.

[Chronos]

Even the Players' Handbook, written before sidekicks were a thing, specifies that Extra Attack doesn't stack with any similar ability, and it's not hard to see that Multiattack is a "similar ability".

[Pildion]

So, if innate spellcasting is what the sidekick uses, would you still calculate its spell save DC / spell attack the same way as a PC? Or just what the stat block says?

[Amnestic]

So, if innate spellcasting is what the sidekick uses, would you still calculate its spell save DC / spell attack the same way as a PC? Or just what the stat block says?

The monster statblock should say what it's innate spellcasting modifier is, and chances are if its a sidekick race its profbonus is +2 at most. Adjust the DC as the sidekick gains a higher prof bonus and any change to their ability scores as necessary.

If you have innate spellcasting for charisma and take wizard, you wouldn't overwrite their innate spellcasting modifier with Int though.

[Chronos]

If you have innate spellcasting for charisma and take wizard, you wouldn't overwrite their innate spellcasting modifier with Int though.
Again, just like a PC. For instance, a PC tiefling wizard still uses Cha for their Hellish Rebuke.

[PhantomSoul]

Even the Players' Handbook, written before sidekicks were a thing, specifies that Extra Attack doesn't stack with any similar ability, and it's not hard to see that Multiattack is a "similar ability".

As Warder says, stacking isn't even an option anyway. (Just like Extra Attack wouldn't stack with itself or with Thirsting Blade because they can't as written, though the PHB does clarify so that they receive marginally fewer tweeted questions I guess.)

[EggKookoo]

Well, that's because Extra Attack adds onto the Attack action, and Multiattack is its own action and separate from the Attack action - the two features don't interact.

This got me thinking. Under Actions, the MM Bandit has simply: Dagger. When the Bandit uses that action, is it an Attack action? Or is it literally a "Dagger" action? If the bandit picked up a second dagger (dropped from an ally, for example), could he use his Bonus to make an offhand attack when he uses his action for Dagger? A strict reading of the rules would suggest he couldn't. Is he even allowed to make a RAW Attack action?

Edit: Scimitar, not Dagger, but it doesn't change the question.

[PhantomSoul]

This got me thinking. Under Actions, the MM Bandit has simply: Dagger. When the Bandit uses that action, is it an Attack action? Or is it literally a "Dagger" action? If the bandit picked up a second dagger (dropped from an ally, for example), could he use his Bonus to make an offhand attack when he uses his action for Dagger? A strict reading of the rules would suggest he couldn't. Is he even allowed to make a RAW Attack action?

From the phrasing of MM 10-11, funnily enough, I guess it's the Dagger Action, so they could lose any Dagger Action benefits if they use the Attack Action (with Offhand Attack option) instead of their Dagger Action. That's kind of funny, actually. (On the bright side, they do have access to the other action options, so they could dual-wield... but maybe they could lose any fun stuff if they have a special damage die or bonus effect.)