Detect Magic: distinguish sensing from inspecting an aura

SRD 5.2.1 · Spell decisions

Before casting

At the table

1. Maintain Concentration and check for magical effects within 30 feet of yourself.
2. If such effects are sensed, take the Magic action to inspect a faint aura around a visible creature or object bearing the magic.
3. Check blocking materials: 1 foot of stone, dirt or wood; 1 inch of metal; or a thin sheet of lead.

Example decision

A caster senses magic in the room, but a magical object is hidden from view inside an opaque container. Does sensing it automatically give a visible aura around that hidden object?

No; the aura step specifies a visible creature or object.

The initial sense and the aura inspection have different requirements. Even after detecting a nearby magical effect, the aura description requires a visible creature or object and a Magic action. The spell does not say it makes hidden objects visible. If a spell created the effect, the aura inspection can reveal its school, not a complete inventory of powers.

Watch for this mistake

Do not import Message’s barrier thicknesses into this spell. Detect Magic lists one inch of metal, and its information is also narrower than the properties and charges provided by Identify.

Ask the table

What has been sensed, what can the caster actually see, and is a barrier blocking the spell?

Source spell

Level 1 Divination (Bard, Cleric, Druid, Paladin, Ranger, Sorcerer, Warlock, Wizard) Casting Time: Action or Ritual Range: Self Components: V, S Duration: Concentration, up to 10 minutes For the duration, you sense the presence of magical effects within 30 feet of yourself. If you sense such effects, you can take the Magic action to see a faint aura around any visible creature or object in the area that bears the magic, and if an effect was created by a spell, you learn the spell’s school of magic. The spell is blocked by 1 foot of stone, dirt, or wood; 1 inch of metal; or a thin sheet of lead.

Source: SRD 5.2.1, 123. Online guide.