Does a Utilize Action interrupt / extend a long rest?

Can you utilize a magic item during a long rest? For example, can you break an Elemental Gem during / at the end of a long rest (after sleeping at least 6 hours)?

Elemental Gem, Red Corundum DMG'24 p257
Wondrous Item, Uncommon
This gem contains a mote of elemental energy. When you take a Utilize action to break the gem, a Fire Elemental is summoned, and the gem ceases to be magical. The elemental appears in an unoccupied space as close to the broken gem as possible, understands your languages, obeys your commands, and takes its turn immediately after you on your Initiative count. The elemental disappears after 1 hour, when it dies, or when you dismiss it as a Bonus Action.

I'd say it's fine:

Interrupting the Rest. A Long Rest is stopped by the following interruptions:

• Rolling Initiative
• Casting a spell other than a cantrip
• Taking any damage
• 1 hour of walking or other physical exertion

A Long Rest is stopped by the following interruptions:

• Rolling Initiative
• Casting a spell other than a cantrip
• Taking any damage
• 1 hour of walking or other physical exertion
• Being Ninja'ed by TarodNet

Since while summoning the Fire Elemental you're not casting a spell, if you aren't rolling Initiative it should not interrupt it. It will disappears after 1 hour so depending what use for it but in and of itself it should be fine.

Quote from Plaguescarred >>

A Long Rest is stopped by the following interruptions:

• Rolling Initiative
• Casting a spell other than a cantrip
• Taking any damage
• 1 hour of walking or other physical exertion
• Being Ninja'ed by TarodNet

Since while summoning the Fire Elemental you're not casting a spell, if you aren't rolling Initiative it should not interrupt it. It will disappears after 1 hour so depending what use for it but in and of itself it should be fine.

 LOL xDDD Didn't see that coming, thanks Plague xD

I don't see why not. Go ahead, have your fun.

Quote from SunIsGettingRealLow96589 >>

"Can you utilize a magic item during a long rest? For example, can you break an Elemental Gem during / at the end of a long rest (after sleeping at least 6 hours"

Notnsure why you would use a one-time magic item like that except for combat, and im not sure you can be in combat without rolling initiative?

The Elemental is summoned for 1 hour after you break an Elemental Gem. If you sleep near or inside the dungeon then an Artificer can get double the number of summons using magical items since he can break Elemental Gems during the long rest and can then Replicate Magic Items at the end of the long rest to create more Elemental Gems. A Lvl 14 Artificer can basically get 10+ CR-5+ summons this way for just less than 1 hour (assumes that the DM interprets different color Elemental Gems as different Magic items for the purpose of RMI).

It is definitely a literal RAW interpretation and probably not going to be allowed by a DM but just trying to understand the Edge Cases (also this approach would make the Artificer very boring to play since all his known RMI Plans would be focused on Summons).

As far as I can tell from the Long Rest rules using a Magic action also does not break a long rest (unless this is considered spell casting).

I was thinking that a more useful example would be to use a Figurine of Wonderous Power during a long rest since the creature lasts for several hours afterwards. However, as I look at this magic item description, I think the live creature IS the figurine and so would disappear if you used RMI to create another Magic Item. At least you could create a new Figurine each day so you would not need to wait for the 6 day cooldown.  

Figurine of Wondrous Power, Bronze Griffon DMG'24 p261
Wondrous Item, Rare
A Figurine of Wondrous Power is a statuette small enough to fit in a pocket. If you take a Magic action to throw the figurine to a point on the ground within 60 feet of yourself, the figurine becomes a living creature specified in the figurine's description below... Bronze Griffon (Rare). This bronze statuette is of a griffon rampant. It can become a Griffon for up to 6 hours.

I could not really see me spending a RMI Plan slot for an Elemental Gem but could maybe see learning how to make a Cube of Summoning. Mechanic is kind of fun since you are not sure what you will get (also you can choose the type of elemental which can allow you to avoid resistances of a final boss). In this case it explicitly says the spell is cast by the cube (and not by you) but still need to assume a Magic action does not interrupt the long rest.

Cube of Summoning DMG'24 p247
Wondrous Item, Rare
This Tiny cube looks like a jack-in-the-box. When you wind its crank as a Magic action, a merry tune emits from the box, the lid pops open, a creature appears in the nearest unoccupied space, and the lid closes. The lid can't otherwise be opened... Roll on the Cube of Summoning table to determine which spell the cube casts to summon the creature. The spell is cast at level 5 (save DC 17, +9 attack bonus) and doesn't require Concentration, but you otherwise function as the spell's caster.

Quote from SunIsGettingRealLow96589 >>

"Each item you create must be based on a different plan you know"

Found it 

Yeah, so having the elemental and a gem at same time would be like having 2 copies of same plan, which the rules do not allow.

The elemental itself isn't a plan. The gem is.

Quote from SunIsGettingRealLow96589 >>

Hang on a second. Did the new artificer rules remove the limitation of one instance of each plan? Like old rules used to be if i had plans for bag of holding, i could only create one bag, even if i could craft 2 items/infusions.

I would have said having a summoned elemental and a gem of elemental summoning would be 2 instances of the same plan. But i dont see that limitation in the latest eberron rules.

If thats true, if you CAN have multiple copies of same plan, id let you build 2 gems and summon them on demand, but that would count as 2 magic items. 

If you can NOT have 2 copies of same magic plan, id say the summoned elemental dissappears the moment you make the new gem. Cause theyre copies of the same plan.

Doesnt really matter what form the object is in, gem, summoned thing, whatever, its still an active instance of the original plan.

Now i gotta read the rules about duplicates...

You can still only have 1 of each Magic Item but when you break the Elemental Gems it summons/creates an elemental and then the gem stop being magical (so Gem and the creature it summons are totally different). So you can create another Gem when that elemental is around without an issue. One possible limitation that is close to RAW is the the DM could interpret the "Elemental Gem" as a plan and only allow you to have one (even though the different Elemental Gems are technically different magical items). In this case they could say you know how to make Elemental Gems and you have to declare the type / color when you make it but you can only make one per day. Honestly this restriction reduces abuse and is more fun.

There are other Elemental Summoning items like the Stone of Controlling Earth Elementals (and the Fire, Air, and Water versions). You could also just learn the plans to all these plus the Cube of Summoning. I think all of these require a Magic action to activate (so should actually still not interrupt the long rest - but DM could disagree) and are definitely different magic items. Once you use one, it cannot be used for another day. However, if you create another one with RMI the previous one disappears. 

As I said above the Figurines of Wonderous Power are different - the creature is the Figurine so if you created another Figurine the creature would disappear.

During, not unless you want to not get any benefits of the rest. At the end, yes but why? What do you have to gain? Unless you know you'll be rolling initiative soon, there's no point.

As a general rule yes. IMO If the magic item casts a spell that was not a cantrip, then no. So sure open your bag of holding, i guess break that gem, but no on wand of fireballs. 

Quote from SunIsGettingRealLow96589 >>

Well, all sorts of shenanigans starts popping up the moment you use this approach with magic plans for making magical tattoos.

Spell tattoo for mage armor. Make it the day before. Near end of long rest, use tattoo to cast mage armor. Then before long rest is over, craft a new magical tattoo for mage armor.

The first casting will last 8 hours. At the end of 8 hours, use remaining/latest spell tattoo to cast mage armor again. So you have 16 hours of mage armor, and didnt use any spell slots.

Any spell that has a long duration (hour or more) could use this. If you are in a dungeon and long rested in a barricaded room, you can come out swinging and know youll be good for the full day.

As much as i like the idea of my artificer being able to make spell tattoos as my plans, this bit of shenanigans says to me that tattoos should be treated like scrolls and not be something an artificer can make from plans.

 

Well, regardless of the answer to the general question, this specific tactic doesn't work the way you want because the rules explicitly say that casting a spell other than a cantrip interrupts a Long Rest. Mage Armor is not a cantrip, so casting it (even from an item) would count as an interruption.

Quote from MyDudeicus >>

As a general rule yes. IMO If the magic item casts a spell that was not a cantrip, then no. So sure open your bag of holding, i guess break that gem, but no on wand of fireballs. 

Yes, I think breaking the Gems is most easily justified as NOT extending the long rest since it is just a Utilize action.

If utilizing a magic item casts a spell it seems like you can justify that this DOES break/extend the long rest (since it is spell casting, even if it is indirect). However, I think a DM could also decide that this does NOT break/extend the long rest since you are not directly casting a spell.

Some other items require a Magic action but do not explicitly cast a spell. This seems like more of a gray area but I am leaning towards assuming that it does NOT break/extend the long rest. However, I think a DM could rule otherwise.

I actually think that Spellwrought Tattoos are not a good idea to use with an Artificer RMI since there is so much potential for abuse. These do explicitly say you are casting a spell (like you are reading a scroll) so I think they would certainly break/extend a long rest.