Can you use a focus to cast the spells and cantrips from the Magic Initiate feat?

[ATHATH]

See the title. I don't see anything that would explicitly grant you the ability to use a focus with your MI spell/cantrips, and being able to use foci of X type is normally explicitly listed as a feature in the entries for each of the spellcasting classes, yeah?

Are racial cantrips also focus-incompatible?

[Nod_Hero]

The PHB "Adventuring Gear" foci list the classes that can use them in their description, so I'd say those are out for a Magic Initiate.

However, there are a LOT of magic items that can be used as a spellcasting focus for a spellcaster.

"If the prerequisite is to be a spellcaster, a creature qualifies if it can cast at least one spell using its traits or features, not using a magic item or the like."

So since ASI is a class feature, and you used the optional Feat rules as that ASI, I would say a Magic Initiate would absolutely be able to use those.

[PhantomSoul]

See the title. I don't see anything that would explicitly grant you the ability to use a focus with your MI spell/cantrips, and being able to use foci of X type is normally explicitly listed as a feature in the entries for each of the spellcasting classes, yeah?

Are racial cantrips also focus-incompatible?

That's consistent with what I'm remembering and seeing. You didn't get the Wizard's Spellcasting Feature with the ability to use a Focus, you just learn two Cantrips and a first-Level Spell.

(Exception being if you take the Feature to access more Spells of your own Class).

[Psyren]

While by RAW the ability to use an arcane/druidic focus (or holy symbol) as a spellcasting focus is unique to the classes that say that in their entries, also by RAW a component pouch is usable by anyone (PHB 151/203) - so if your DM is a stickler against using a focus with MI, just use one of those instead.

[Narbaculus]

Also, MI gives you spells from a specific list. They aren't just spells; they're bard spells, druid spells, wizard spells, etc. So, if you have something that lets you use a spellcasting focus for "your wizard spells" (like the Wizard's Spellcasting feature), you could use it with the spells you know from Magic Initiate as well.