I'm curious, where EXACTLY does it define multi-attack as NOT an attack action.
The actions in combat state that there are ATTACK, CAST A SPELL, DASH, DISENGAGE, DODGE, HELP, HIDE, READY, SEARCH, and USE AN OBJECT.
Secondly, page 194 it states,
If there's ever any question whether something you're doing counts as an attack, the RULE IS SIMPLE; if you're making an attack roll, you're making an attack.
So what is an attack roll?
you're attack roll determines whether the attack hits or misses
On page 195 under melee attacks it even DEFINES a monster attack as using "claws, horns, teeth, tentacles, or other body part."
Furthermore, to show that the multiattack seems to qualify as an ATTACK ACTION...the ranger ability, multiattack defense (pg 93) states that when you are hit with an attack, you gain a +4 bonus to AC against all subsequent attacks made by that creature for the rest of the turn.
Everything that says it does NOT count as an attack action, seems to be a HOUSERULE rather than a hard fast rule of the rulebooks.
Is there ANYONE THAT can actually quote a book and page number for where it actually spells out multiattack is not an attack action, because everything I've read seems to INDICATE that it IS in fact an attack action.
The Monster Manual defines it as different than a single melee attack (which is also an attack action) which is the reason why it cannot be used for an opportunity attack, but nowhere that I can find does it state it is not an attack action.
In fact, it seems to match the definition of attack action from anything I read in the books.
HOWEVER, it is NOT defined as an attack action (beyond the obvious statement that when you make an attack roll, that counts as an attack action, or that the attacks under multiattacks are listed as attacks under the attack section of the PHB) or NOT as an attack action specifically either...
To me, this means it's one of those hazy areas where it comes down to WHATEVER THE DM RULES.
That is simply because I cannot find a specific statement one way or the other (except where it states if you are rolling to make an attack with that action, it is an attack action, and you certainly are rolling to make an attack with multiattack).
On the otherhand, the above is Rules as written. Rules as Indicated, or the spirit of the rules may be different. As per page 164 under the Extra Attack with multiclassing, it would indicate, or the spirit of the rules would seem that it would NOT stack with extra attack as per the idea that Extra Attack does not stack or add together if you gain it from more than one class.
Furthermore, you could say the text is exclusionary in regards to the Extra Attack text vs. that of the multiattack where it states...
you can attack twice, instead of ONCE, whenever you take the Attack Action.
As you are NOT attacking ONCE with the multiattack, it would not qualify as an Attack that you can use with the Extra Attack Ability...
But that would be a DM houserule to clarify in MY case, I don't actually have anything to say that is the official way of the rulebooks except for my OWN ruling.
If someone has it where it is specifically stated...I'd be interested...but though things may agree with how I have houseruled it for CLARITY...and how I think it goes with the spirit of the rules...I don't see anything that actually spells it out in the actual rules as written.
I think it's another one of those vague areas that is left up to the DM to interpret.