[RPG] Detect Magic as Ritual casting to find magic item

dnd-5edurationspellcastingspells

I am new as DM running my fourth session playing D&D 5e.
I have five experienced players who sometimes use logic that seems suspicious.

One of my players is a wizard. They cast Detect Magic as a ritual to search for magical items, barriers, or a person who has magic.

I don't have a problem with them walking while casting detect magic as a ritual, but the problem is about the size of the area.

The party thinks they can scan the area during their ritual while walking with a 30 feet radius while casting.

So in 10 minutes, the wizard can scan the area using detect magic.

Is that possible? It feels broken on some level.

Best Answer

Your players misunderstand how rituals work.

Casting a ritual adds a time cost of ten additional minutes to the casting time. So casting Detect Magic this way takes one action and ten minutes before they gain the benefit of the effect.

Detect Magic has a regular duration of ten minutes, but your players need to cast the spell first before they can use it - they can either do so by using a spell slot or spending the additional time cost of the ritual. Rituals:

Certain spells have a special tag: ritual. Such a spell can be cast following the normal rules for spellcasting, or the spell can be cast as a ritual. The ritual version of a spell takes 10 minutes longer to cast than normal. It also doesn't expend a spell slot, which means the ritual version of a spell can't be cast at a higher level.

For more information read the section about Casting Time.

Also note that Detect Magic is a spell that requires concentration, so the wizard needs to maintain concentration while scouting out the area.

Some spells require you to maintain concentration in order to keep their magic active. If you lose concentration, such a spell ends. [...]

Normal activity, such as moving and attacking, doesn't interfere with concentration. The following factors can break concentration:

  • Casting another spell that requires concentration. You lose concentration on a spell if you cast another spell that requires concentration. You can't concentrate on two spells at once.
  • Taking damage. Whenever you take damage while you are concentrating on a spell, you must make a Constitution saving throw to maintain your concentration. The DC equals 10 or half the damage you take, whichever number is higher. If you take damage from multiple sources, such as an arrow and a dragon's breath, you make a separate saving throw for each source of damage.
  • Being incapacitated or killed. You loseconcentration on a spell if you are incapacitated or if you die. [...]

Also note that the penetrative magic detection of Detect Magic is restricted by materials:

The spell can penetrate most barriers, but it is blocked by 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt.

So while the way the players used Detect Magic to scan an area within 10 minutes with a 30 feet radius is correct, they disregarded the cost to ritual casting - and there are additional things that you have to consider when they use Detect Magic like materials blocking off vision, concentration, and time, or spell slot cost - all of which are limited resources in dangerous situations.