Does a Glyph of Warding have its own agency or a limited omniscience in the game?

Question

The case of the nasty Drow, invisible evil Sprite and the blue Orc.

Some specifications for the trigger of a Glyph of Warding are more obvious than others. For instance, I am a Dwarf Cleric and set a Glyph of Warding (Explosive Runes) underground to be triggered by the next Drow that walks past my favourite stalagmite. It is simple: I can see under ground because of my Darkvision; I know what a Drow is. Therefore the Glyph of Warding's trigger is something that I could potentially see and/or know.

Now, what happens when I set the trigger to be an invisible evil Sprite? I can't normally see these creatures. So, in this case does the Glyph of Warding still trigger when an "invisible evil Sprite" passes by and "Kaboom! Bye-bye evil Sprite!". Also, how can it know that Sprite is evil, when I don't even know that?

Then there is this situation: I am a completely colour-blind and my mission is to capture the blue Orc without breaking my cover, by say asking every punter a stupid question like: "Have you seen a blue Orc around these parts, me matey?!" So, I come up with a plan. I use a Glyph of Warding on a bridge which most of the village use on a regular basis. The trigger is: when a blue orc walks over the slab of stone, cast Light. I lie in waiting, watching out for my Light cantrip to trigger. Once I spot the blue Orc, I will follow her/him and plan the capture.

So Orc-ward...!

There is a deeper question at the heart of my question in that Glyph of Warding appears to have its own sense of agency in the game. The magic cast, that recognises the specific conditions for a trigger, appears to be observant and have possibly a omniscience limited to its immediate surroudings.

So, does a Glyph of Warding have its own agency or a limited omniscience in the game?

Glyph of Warding

You decide what triggers the glyph when you cast the spell. [...]

You can further refine the trigger so the spell activates only under certain circumstances or according to physical characteristics (such as height or weight), creature kind (for example, the ward could be set to affect aberrations or drow), or alignment. You can also set conditions for creatures that don’t trigger the glyph, such as those who say a certain password.

When you inscribe the glyph, choose explosive runes or a spell glyph.

This feels like it's not quite the question you mean to ask. "Having its own agency" is pretty far removed from any practical consequences. — Mark Wells, Feb 04 '20 at 23:33
It may be more helpful to ask about what you think it can do that you're not sure about. It's unclear to me what you're asking, unless you're just asking how the glyph knows (which is possibly opinion based, but there might be lore about it.) — NotArch, Feb 05 '20 at 01:19
The way this question is asked makes me wonder if the glyph is expected to get creative with its triggering condition - who says that the evil Sprite can't be a random evil NPC who just happens to be called Sprite by their peers? — Michael Schumacher, Feb 05 '20 at 17:30
@40355saysReinstateMonica Thank you.Yes, I guess it's a very limited agency in that it is only about checking out for a yes/no condition and it can't vary from that, but there is a level of interpretation and omniscience in it which is interesting. I will tidy this up. Thanks — Senmurv, Feb 05 '20 at 21:20
Related: What is the limit to a Glyph of Warding's trigger?. See also: Can your own death be a trigger for Glyph of Warding?, Is there a limit on the "detection range" of Glyph of Warding's trigger?, Can the Glyph of Warding spell detect whether a creature passed or failed a saving throw?, Does a Spell Glyph need to "see" the target to activate? — V2Blast, Feb 05 '20 at 21:32

Amethyst Wizard · Accepted Answer · 2020-03-01T05:42:11.037

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The inscribed glyph is magic.

Your character's corporeal capabilities are more limited than those which he draws upon by manipulating the subtle weave of magic inherent to the cosmos.

Wizards are not taught to imbue the glyph of warding with agency, it is not a sentient inscription.

You specify a trigger that may activate the ward. The trigger can include the approach of a creature with a chosen alignment; such as the "evil sprite" in your example.

Your character may not be able to sense the alignment of another creature, or it's other features, but your powerful use of magic will guide the inscription to activate when the appropriate conditions are met. The magic of the multiverse will make it so.

edited Mar 01 '20 at 05:42

answered Feb 05 '20 at 02:12

Amethyst Wizard

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Yup. Because magic. +1. – NotArch Feb 05 '20 at 02:16
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I can't help but think that this is a slippery slope. What if the trigger were "when a creature that intends me harm enters this square"? Or "when a creature that has kicked a puppy at least once in its life crosses this line"? What's to stop it from being an infallible engine for detecting lies, criminals, or shapeshifters, etc? This is arguably a correct raw interpretation, but I think it is dangerous to apply without house rules - i.e. the spell is likely broken out of the box. – cpcodes Feb 05 '20 at 18:19
@cpcodes Thank you. Would you be able to post it as an answer as it is a really important point you make here! – Senmurv Feb 05 '20 at 21:27
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@cpcodes DM adjudication on a trigger is not a house rule. – NotArch Feb 05 '20 at 21:50
@cpcodes Would those really be so broken? Magic is already capable of solving a lot of problems in D&D directly, and casting the spell takes an hour and a minimum of one 3rd level slot. I'm not saying it's not abusable, but is the danger of routine, meaningful abuse that high? – Upper_Case Feb 05 '20 at 22:26
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@Upper_Case Magic is capable of solving a lot of problems, but one of the things it generally can't do is make decisions for you, and it's essential that it can't, because making decisions is the way players participate in the game. This is exactly the issue with Glyph of Warding: it's perilously close to being better at making decisions than the player can be. – Mark Wells Feb 06 '20 at 01:19
@cpcodes "physical characteristics, creature kind, or alignment.". You can't put a trigger on other conditions. You can't put a trigger on the past/future history of this creature ("explode when otherwise this creature would have harm me later", "light if this creature will win next week's caucus") – Cœur Feb 06 '20 at 08:01
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"light if this creature is going to return safe and successfully from the quest to kill the evil sorcerer" ... then only attempt the quest if it triggers a light for yourself... – Cœur Feb 06 '20 at 08:07
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Perhaps worth mentioning the behaviour of the Glyph is quite comparable to old fairy-tale interpretations of magic, especially guards and wards and curses that lift "when one pure of heart approaches" or "when you meet your true love" etc. In those cases, the magic served literally as a plot device to show that the correct thing had happened even though the original caster and often the person triggering the special event did not know or have ability to detect the trait being measured. – Neil Slater Feb 06 '20 at 10:25
@NeilSlater Yes agreed, another classic, forty thieves “open sesame” – Amethyst Wizard Feb 06 '20 at 10:52
@MarkWells What decisions is the glyph making? It's simply responding to things that are true, at least in the examples given. I'd think that the risk is more along the lines of imitating other spells, but even then the glyph is just indicating whether or not certain things are true. Maybe there's a case that's just not occurring to me. – Upper_Case Feb 06 '20 at 14:49
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@Cœur "physical characteristics, creature kind, or alignment" is only half of the allowed triggers. "Certain circumstances" is the other half, and it is vague enough to cover a number of scenarios. That is what this discussion is trying to address within the rules and finding that there is no recourse in the rules to address it. This requires DM adjudication, and not just for edge cases and NautArch seems to imply, but the spell essentially claims "this spell can do anything and everything" and the DM then has to say "well, at my table...". This especially fails for AL play. – cpcodes Feb 06 '20 at 17:20

score 22 · Answer 2 · edited Jun 16 '20 at 10:23

The rules do not say

The rules do not specify whether the glyph spell does or does not possess agency. It is possible to create perfectly sensible implementations of the rules that don't give the glyph agency. It is also possible to create perfectly sensible settings where the glyph does have agency. The rules expect to be adapted into a wide variety of setting implementations and this omission, like many, exist therefor, so that the content they are attached to can be used without major modification in a wide variety of campaigns.

Detecting stuff you can't otherwise detect in no way implies agency

Your examples of agency seem to have nothing to do with the concept. An agent is an entity that makes choices. Your examples have to do with 'knowing' stuff you don't know, where knowing means differentiating on the basis of. That's not a very unusual trait-- you would have a hard time judging the volume of a metal sphere but if you put it in a partially-water-filled graduated cylinder the cylinder can tell you how much volume it had. That's not evidence that the cylinder is alive, it's evidence that the cylinder is a measuring device. Your examples, likewise, show that the glyph is a potent measuring device, but there's no reason to suspect cognitive abilities of any kind on that basis.

Does a Glyph of Warding have its own agency or a limited omniscience in the game?

Glyph of Warding

2 Answers2

The inscribed glyph is magic.

The rules do not say

Detecting stuff you can't otherwise detect in no way implies agency

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