Does making an ability check take an action? [duplicate]

Question

The only ability checks that are listed as an action in the game are Dexterity (Stealth) when taking the Hide action, and Wisdom (Perception) or Intelligence (Investigation) for the Search action. Do any other ability checks require an action?

My fighter was chasing a floating target, and needed to climb up a short but steep cliff. The climb and horizontal run to the target were within his movement for the turn, but the DM had me roll a Strength (Athletics) check to complete the climb. I was successful, but after arriving at the top and attempting to grapple my target, the DM declared that I had already completed a skill check, which was an action. I was able to grab the target using Action Surge; however, I felt slighted, as I thought the climb shouldn't have taken an action.

Who was right here? If the ability check was an Intelligence (Arcana) check to recall some information, should that still require an action as well?

Answer 1

So I think there's two problems that have to be answered in your question: whether or not climbing can invoke an ability check, and whether or not climbing should require your action.

Whether or not a particular character behavior requires an ability check is dependent on the DM, unless the rules have reified that behavior as requiring an ability check. So it's fully within the DM's purview to say "climbing this sheer cliff requires a Strength check, you can add your athletics proficiency", or to elide that check for any reason at their discretion.

However, climbing a cliff is governed within the general rules on movement:

Each foot of movement costs 1 extra foot (2 extra feet in difficult terrain) when you're climbing, swimming, or crawling. You ignore this extra cost if you have a climbing speed and use it to climb, or a swimming speed and use it to swim. At the DM's option, climbing a slippery vertical surface or one with few handholds requires a successful Strength (Athletics) check. Similarly, gaining any distance in rough water might require a successful Strength (Athletics) check.

―Climbing, Swimming, and Crawling, Player's Handbook, pg 182

As you can see from the quoted rules here, there's already a cost baked into the act of climbing, whether or not it includes making an ability check to successfully do it. Although the DM is technically allowed to impose Action Economy costs on top of this (as they are with any other behavior not explicitly reified as such in the book), they really shouldn't have in this case. Climbing is a type of movement, and should be treated as such.

My best guess, without personally knowing your DM, is that they may have been thinking of rules from other editions of D&D, or possibly other d20-based games (like Pathfinder) where such checks may have required the use of the character's action. My guess is based on the colloquial use of the term "skill check", which don't exist in 5e anymore―5e has "ability checks", which may or may not add your skill proficiencies to the roll depending on the type of check or the DM's discrepancy. Before your next session, I would talk to your DM about revising this case (and other cases that involve special movement speeds).

One other thing I'm going to add, because I saw it mentioned in comments below and figure it's good advice that should receive visibility: if the DM is going to associate an Action Economy cost to behavior that isn't reified as such in the books, they should convey that to the player before the player makes the decision to do it. I can understand unusual circumstances where an action to climb over a wall might be appropriate (perhaps the DM is inferring the player is taking the Dash action to get some extra distance?) but if that's the case, the DM should be stating that outright so that the player can make choices about how they want to spend their turn.

Answer 2

The DM decides if there is an action economy cost associated with making an ability check.

This is covered in the section Improvising an Action:

Your character can do things not covered by the actions in this chapter, such as breaking down doors, intimidating enemies, sensing weaknesses in magical defenses, or calling for a parley with a foe. The only limits to the actions you can attempt are your imagination and your character’s ability scores. See the descriptions of the ability scores in chapter 7 for inspiration as you improvise.

When you describe an action not detailed elsewhere in the rules, the DM tells you whether that action is possible and what kind of roll you need to make, if any, to determine success or failure.

The call your DM made seems well within the boundaries of the guidance in the rules. The rules for climbing state:

At the DM’s option, climbing a slippery vertical surface or one with few handholds requires a successful Strength (Athletics) check. Similarly, gaining any distance in rough water might require a successful Strength (Athletics) check.

So your DM decided the climb required a successfully Strength (Athletics) check, then determined that doing so cost an action. This is well within the guidance from the rules. I have ruled it both ways in similar situations before, depending on the details of the situation.

When my players ask about ability checks during combat, or when what they are trying to do requires an ability check, I always advise them what the action cost would be before they make their decision to do it. It seems this is the communication gap between you and your DM.