Looking Around During Combat: Is an Action or Ability Check Necessary?
Updated: Feb 22
Your party is backed up against the castle wall by a horde of skeletons. You've destroyed dozens, but they keep coming, slowly wearing the party down. You are trapped. Almost. In the recesses of your memory you recall that somewhere in this area of the wall is a portal, secret but marked (to those who know) with a small stone relief of the smirking face of a hooded monk. You desperately search for it. Does your search use up an action? What about an ability check?
An action is necessary. The Player's Handbook lists Search among the "Actions in Combat" and provides:
"When you take the Search action, you devote your attention to finding something. Depending on the nature of your search, the DM might have you make a Wisdom (Perception) check or an Intelligence (Investigation) check." (PHB p. 192.)
Jeremy Crawford has reiterated this rule. It makes sense that searching for the secret door marker would take an action. That fact that it is small and you don't know its precise location would lead me to conclude, as DM, that if you want to have any chance of finding it, you would have to devote your attention to finding it. That means taking an action.
Quick glance. Matthew Mercer has suggested that use of Perception during combat does not always require an action: "A perception check can be a quick glance." Does he disagree with the official rule? I don't think so. A quick glance is not the same thing as devoting your attention to finding something. Although I believe a quick glance would not be a sufficient effort to find the secret door marker in our situation, it might enable you to see something that is in the open and large enough to be within your line of sight when you simply turn your head one way or another. Like looking for a nearby party companion or particular foe, or identifying the closest non-secret doorway.
Can a quick glance involve Investigation? Matthew Mercer says no. I agree. Investigation is defined as follows:
"When you look around for clues and make deductions based on those clues, you make an Intelligence (Investigation) check. You might deduce the location of a hidden object, discern from the appearance of a wound what kind of weapon dealt it, or determine the weakest point in a tunnel that could cause it to collapse. Poring through ancient scrolls in search of a hidden fragment of knowledge might also call for an Intelligence (Investigation) check." (PHB p. 178.)
None of these examples could be possible with a quick glance. The time it would take to gather the sensory information (often visual), and then to use your faculty of logic to make a deduction from such information, would exceed the fraction of a second used to make a quick glance.
Whether an ability check is required when you search for the secret door marker during combat is a separate question from whether an action is necessary. Here is the rule on ability checks:
"The DM calls for an ability check when a character or monster attempts an action (other than an attack) that has a chance of failure. When the outcome is uncertain, the dice determine the results. (¶) For every ability check, the DM decides which of the six abilities is relevant to the task at hand and the difficulty of the task, represented by a Difficulty Class. The more difficult a task, the higher its DC. The Typical Difficulty Classes table shows the most common DCs." (PHB p. 174.)
Given the small size of the thing that you are looking for (the secret door marker), that you know its general but not specific location, and that you are in the middle of combat, I would conclude as DM that the outcome of your search would be uncertain. A Wisdom (Perception) check would be necessary. An Intelligence (Investigation) check would not; you are not trying to decipher something. You are simply trying to find the marker.
What about the quick glance — is an ability check necessary? Just as with a bona fide search, it depends if there is a chance of failure. The Dungeon Master's Guide provides further guidance on uncertainty:
"When a player wants to do something, it’s often appropriate to let the attempt succeed without a roll or a reference to the character’s ability scores. For example, a character doesn’t normally need to make a Dexterity check to walk across an empty room or a Charisma check to order a mug of ale. Only call for a roll if there is a meaningful consequence for failure. [¶] When deciding whether to use a roll, ask yourself two questions: Is a task so easy and so free of conflict and stress that there should be no chance of failure? Is a task so inappropriate or impossible — such as hitting the moon with an arrow — that it can’t work? [¶] If the answer to both of these questions is no, some kind of roll is appropriate." (DMG p. 237.)
For example, during combat against the skeletons you quickly glance around looking for the dwarf fighter in the party. If she is close by and not obscured by a skeleton lord on horseback or some other large object, then as DM I would simply conclude that you spotted the dwarf. If the dwarf is not so conveniently located, then a Wisdom (Perception) check would be necessary, with the Difficulty Class set accordingly. If the dwarf is so obscured or otherwise difficult to see, or if she is simply not within eyeshot, then I would either let you roll your ability check but automatically fail you or simply tell you that you don't see the dwarf.
Wrapping it Up
So, actions and ability checks are two separate notions. An action is D&D's concept that regulates how many things you can do during a 6-second combat round. An ability check is D&D's concept that is used when what you are trying to do (other than attack) has a chance of failure. As discussed above, sometimes one or the other is required, sometimes both are required, and sometimes neither is required.
The searching during combat rule is summarized in the table. And the skeleton horde? You find the small stone relief of the smirking monk's face. It takes three rounds, using an action and making an ability check each round. On the following round you take the Disengage action and move toward the marker, and press on it with your hand. This instantly releases a mechanism allowing a large stone block to rotate on an axis. After using your free "communication" to alert your party to the secret door, each of your party uses the Disengage action and retreats through the portal. Whew.