One of my players cast the contingency spell with the next circumstance: "When I blink VERY hard the contingency takes effect". He stored on the contingency a 5th level "Armor of Agathys" spell.

So right now he's trying to "blink really hard" the first time a melee creature attacks him, outside the player's turn. He's even trying to do it just before the melee attack hits him (so the attacker can't rethink his target).

Keeping RAW in mind: Can he do it?

Right now I'm ruling that "blinking really hard" outside his turn consumes his reaction. And, that when he tries to blink just before the attack hit, he must do a dexterity check against the creatures attack roll to succeed.


3 Answers 3


Yes, sort of, but not how he wants to

Yes, you can use a Reaction to trigger a Contingency. That's fine and pretty straightforward. You have to set up the Reaction ahead of time though, as usual: either by threatening a creature's space and it causing you to gain an Attack of Opportunity Reaction, or by Readying an action ahead of time (every round) causing you to gain a Reaction opportunity.

Because blinking isn't an attack that can take advantage of an AoO, that means he's limited to Readying “blink very hard when attacked” to gain a Reaction. That sounds like a terrible waste of his Reaction and Action every round that he isn't attacked, but it's possible to do. Terrible, but possible.

What he can't do is gain a Reaction option from nowhere — just like Bonus Actions, he can take up to one Reaction, but that doesn't mean he can choose to make a Reaction just because he wants to. A PC has to have an option that they're already allowed to take (like the one created by Readying), and that option (when used), counts as their one Reaction for the turn. You can't just make a Reaction because you want to.

That's what he's trying to do: get a free Reaction opportunity without having any ability allowing him to take a Reaction then.

What about things that wouldn't take an action? Blinking isn't an action!

But isn't the trigger trivial? Why does it need a whole Reaction? You can just talk whenever, after all, and blinking is something we do all the time already.

The problem is that as a reaction to an attack it's not just doing something anymore, it's doing something with specific timing in response to an attack. To pull that off you have to get the timing right, or it doesn't work. There's a mechanic for this conveniently built into the game, that dictates how such critical-timing activities can be done in reaction to a situation: the Reaction action type, and Readying to prepare one.

So although blinking very hard is inconsequentially trivial on its own, the consequence of timing it wrong in response to an attack is such that it can't be done for free anymore, and the most appropriate model for such an endeavour is the Reaction mechanics, including Readying to acquire a Reaction opportunity.

As a last note, to cover any objection to the assertion I make above that you have to get the timing right or it won't work: if you don't want the precision of Readying for your Reaction, then you're OK with just doing it whenever. And that's what your own turn is for.

  • 3
    \$\begingroup\$ Making the trigger "When I cast the shield spell" would do the trick \$\endgroup\$
    – Dale M
    Commented Sep 26, 2016 at 20:09
  • \$\begingroup\$ @DaleM The trigger for contingency, you mean? On first thought, that'd probably work… Probably a poor way to use three spell slots though. \$\endgroup\$ Commented Sep 26, 2016 at 20:12
  • \$\begingroup\$ That was just the first thought that popped into my head - you could tie it to anything that gives you a reaction. \$\endgroup\$
    – Dale M
    Commented Sep 26, 2016 at 23:22

Yes, you can, but it still requires using the action economy.

It seems that the whole question could be sidestepped by making the trigger "whenever a creature targets me for an attack".

Making the trigger an act that you have to consciously perform seems to ignore the whole utility of Contingency, i.e. to automatically cast a spell when an event happens, requiring no usage of the action economy from the caster. Consider:

The contingent spell takes effect immediately after the circumstance is met for the first time, whether or not you want it to

The intent here is an external agent/event triggering the contingent spell. Your choice is not normally an issue.

Yes, you could make the contingency something you could perform, but that would require the sort of timing that Readied Actions and Reactions are put into the game to cover. Not a good use of the spell.

  • \$\begingroup\$ The advantage of the blink really hard approach would be player input. Ie. you get to decide when attacked if the attack is significant enough to warrant firing the contingency. \$\endgroup\$
    – Taemyr
    Commented Sep 27, 2016 at 12:08
  • 1
    \$\begingroup\$ This would be offset by the disadvantage of having to use the Ready action, or at least your Reaction in the case of a lenient DM. Personally, if I were a warlock with that high a level of spell slots, I'd cast successive Armor of Agathys spells, and take the first hit. \$\endgroup\$ Commented Sep 27, 2016 at 13:31

It's a valid use of a reaction and it's fine for you to require it.

The relevant text for Contingency from PHB p. 227 says...

...it takes effect when a certain circumstance occurs. You describe that circumstance when you cast the two spells. For example, a contingency cast with water breathing might stipulate that water breathing comes into effect when you are engulfed in water or a similar liquid.

So the relevant circumstance here is, "when I'm blinking very hard". So far so good.

Reactions are described on PHB p.190 as...

Certain special abilities, spells, and situations allow you to take a special action called a reaction. A reaction is an instant response to a trigger of some kind, which can occur on your turn or on someone else's."

"Blinking really hard", in response to being attacked sounds like, "an instant response to a trigger of some kind", so we're all good. His contingency spell makes being attacked a situation that allows him to use a Reaction to trigger his contingency spell.

Some additional validation that you're fine to require his reaction be used for this is available on PHB p. 190 under, "Other Activity On Your Turn",

The DM might require you to use an action for any of these activities when it needs special care or when it presents an unusual obstacle.

Which easily covers blinking in a special way while under attack. However, there doesn't seem to be any reason this should require a dexterity check any more than an attack of opportunity, or any other basic Reaction, should.

  • 4
    \$\begingroup\$ Reactions are limited to "Certain special abilities, spells, and situations." nothing described here qualifies. \$\endgroup\$ Commented Sep 26, 2016 at 19:46
  • \$\begingroup\$ @DerekStucki The special situation is being attacked and this is clearly covered in my answer. \$\endgroup\$
    – Ceribia
    Commented Sep 26, 2016 at 19:48
  • \$\begingroup\$ I think the gist of what you're trying to say is that the Contingency spell has a trigger and triggering that can be done at any time, depending on what it is. In the case of something very, very minor like blinking very hard, that may not even be substantial enough to require any kind of Action at all. Does that sound about right? \$\endgroup\$
    – Javelin
    Commented Sep 26, 2016 at 20:28
  • \$\begingroup\$ @Javelin Close, but that would be an alternate interpretation. I'm saying the rules allow for the dm to require an action for activities that need special care, blinking is a minor thing that would generally require no action, and instead requiring a reaction here makes sense in context of the spell and what a reaction is generally used for. \$\endgroup\$
    – Ceribia
    Commented Sep 26, 2016 at 20:49

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