Assuming I do not have access to a second 9th level spell for that day (such as via a Boon, a scroll, or an item), when I cast glyph of warding at a lower level than 9th, can I use wish to supply the second spell?
The key considerations I am thinking about are that if I replicate a spell using wish, that spell is cast using a 9th level slot; that, and the highest level spell that a glyph of warding can store is equal to the level of the spell slot it was cast with.
Here's glyph of warding:
You can store a prepared spell of 3rd level or lower in the glyph by casting it as part of creating the glyph...
The first problem is that a spell created via wish is not a prepared spell. (Wish itself is, but it's not the spell you're storing in the glyph.)
The second problem is that you have to actually cast the spell, and wish doesn't cast spells; it duplicates them.
Casting a spell requires performing the components. The rules are fairly emphatic about this:
A spell's components are the physical requirements you must meet in order to cast it... If you can't provide one or more of a spell's components, you are unable to cast the spell.
And specifically for material components:
But if a cost is indicated for a component, a character must have that specific component before he or she can cast the spell. If a spell states that a material component is consumed by the spell, the caster must provide this component for each casting of the spell.
Wish bypasses all of this, including the requirement to provide specific material components, and that's because it doesn't cast the spell. The verb it uses is "duplicate".
The third problem is that wish says that "the spell simply takes effect". But glyph of warding precisely requires the spell not to take effect just yet. It overrides the normal mechanics of casting the spell, but it doesn't override wishing the effect into existence.
Jeremy Crawford tweeted the following.
A spell you duplicate with wish can be cast at a higher level, as long as that level is no higher than 8th.
The wording of Wish for casting other spells is:
The basic use of this spell is to duplicate any other spell of 8th level or lower. You don't need to meet any requirements in that spell, including costly components. The spell simply takes effect.
Glyph of Warding have the following phrase:
Spell Glyph. You can store a prepared spell of 3rd level or lower in the glyph by casting it as part of creating the glyph. [...] If you create a spell glyph, you can store any spell of up to the same level as the slot you use for the glyph of warding.
For example, you can cast Glyph at 5th level, then use Wish to cast Planar Binding, Wish would null the material cost of Planar Binding.
Just remember that Wish can only replicate spells up to 8th level. So you could use your 8th level slot to cast Glyph then use Wish to store any 8th level or lower spell.
