I don't understand what this is supposed to even mean? What is a reaction status exactly?
A spell casting time requiring a reaction use the same type of action as an opportunity attack or the readied action. It is subject to the same rules affecting reactions and wouldn't be usable if incapacitated for exemple. So not sure what you mean here....
Can you quote the rules where this is written?
PHB, 190, Reactions: "Certain special abilities, spells, and situations allow you to take a special action called a reaction."
PHB, 193, "Ready" section. "To do so, you can take the Ready action on your turn so that you can act later in the round using your reaction."
"When the lrigger occurs, you can either take your reaction right after the trigger finishes or ignore the trigger."
There's no reaction status. There's the same difference that runs between "a melee weapon attack" and " an attack with a melee weapon". If you can't use the reaction to fire your action, you can't fire your action, and that's obvious.
That is not the case. The reaction to a trigger cannot come before that trigger. This is true not only for 5E but in the wider universe, ignoring quantum physics. It has nothing to do with 'Actions In Combat', or 'turns'.
What??? What are you even saying? Where did i say what you are implying - no, stating - i'm saying?
It has to do with rules for the Ready action, thus has to deal with Actions in Combat and turns, but... whaaaat? We are in agreement on the trigger...
If your trigger is, 'when he shoots me, I shoot him', then yes his shot goes first because the trigger is him shooting you. This is why no sane person would choose that trigger!
If your trigger is, 'when he draws his gun', then he draws his gun and that triggers your shot. You shoot him after he draws his gun but before he shoots you, because your trigger had nothing to do with him shooting you.
This is where i (as in, in every post i made till now i tried to say "i , as a DM" or "personally") split.
Case 1) Yep. We agree. Crystal clear rules.
Case 2) is actually case 2 AND case 3.
Is the weapon being drawn as part of the Attack action?
Case 2) Yes it is!
Case 3) No, it's an Use Object action!
By rules, the trigger is "i draw the gun". You go after the trigger has come to an end. The gun has been drawn. TO ME and my players, ONLY case 3) actually lets you shoot. case 2) shoots after the Attack action has resolved.
This is MY general ruling. I supposed it was apparent by my (supposed) apparent change of person.
If your trigger is, 'if he goes for his gun', then the DM describes exactly what he does. If you perceive what he actually does as 'going for his gun' (skill contest may be required) then you can choose to execute your Readied action. Again, no part of the trigger involved him actually shooting you, therefore you don't have to wait for an action subsequent to your trigger is resolved! Only for the trigger itself to resolve, and you make damn sure that you don't choose his actual attack as your trigger!
This is exactly why your player has to state a CLEAR trigger. And this is not. You shouldn't be bothered each time to describe each half of a millimeter of cruising hand, to understand whn your player intended his action to take place. It is that simple, yet the fact that his idea of "go for the gun" and your idea of "go for the gun" might be different and worth a roll, or even a roll to see if he actually makes it fast enough, should be an indication that something is not right. Rules for simplicity and pacing. If you want to rule it that way, that's your call. For me, i try to avoid it as much as possible.
There is nothing in the rules for the Ready action that require the trigger to be an Action In Combat!
No, and it has not to be. It can be movement, for example. It can also be "the action that has no name and it's really not an Use Object action" that lets you activate a magic item.
It is perfectly permissible to define your trigger as 'if he starts casting a spell',
No it's not. You are no mind reader. You cannot know that "he is about to cast a spell", but "oh he started casting" it's too late, the casting comes to pass before your action, because the trigger is the casting, not the starting. No matter how much a player can complain about it.
because 'casting a spell' is 'the VSM components', not 'the spell effect beginning'.
Citation, please. Also, the trigger for your second example would be "a spell has been cast". And the first is "when he casts a spell" by your own definiton.
The trigger is the VSM components. By rule, your Readied action resolves after the trigger but before anything else. So the VSM components complete, then your reaction/Readied action resolves, then the spell effect begins, if it still can.
The trigger has to be an action. Not an Action, just an act. The act has come to pass. VSM is not an action. There's no rule ANYWHERE that describes HOW a spell is cast, except that you can use the free hand you have to have for material components to make the gestures. This is it. If any of this was not true, you could
- define the Trigger as "rock", making the whole thing meaningless
- singlehandedly chose how your target is doing something, it's not in your sphere of influence.
- break the "trigger has to pass", houseruling.
There's nothing that states that the casting of a spell is nothing more than a flick of a staff and the word "peanut" uttered in chinese, that it can happen at the same time. The casting of a spell is a single action, and actions CANNOT be interrupted unless exceptions.
Your Readied action hasn't interrupted the trigger (the VSM components) at all! But your Readied Action still resolves before the spell duration begins because the spell effect was never the trigger!
Do you get it yet?
Who cares? The spell has been cast. If it's a charme, your attack is going to hit before the target has a chance to utter a word other than the one needed for V. His target is charmed, you roll for damage, caster is dead. Any difference? No. So?