What's the best way to handle new objects placed inside a permanent shrink item chest?

Question

A caster has Leomond's secret chest and casts shrink item to carry it around (while it's not on the ethereal plane) regularly enough to warrant spending the experience points to cast permanency on it. (hasn't happened yet but I anticipate that it might)

Would the permanent shrink item spell effect take into consideration the contents of the container each time the command word is spoken, shrinking the chest and its contents as one item, and reverting it as one item?

Or, would the chest itself shrink and the contents burst out explosively?

One reason for uncertainty is that the spell states that each time the shrunk item is restored the spell ends.

Restoring the shrunken object to its normal size and composition ends the spell.

The ordinary duration for this spell is the length of time that an object may remain shrunk; Under the permanency spell, the duration is changed to permanent, meaning that it can retain it's shrunken form indefinitely and, in addition, an object can be shrunk and restored an indefinite number of times.

"It's only described that it can be shrunk and restored an indefinite number of times, but the spell effect is still ended when the object is restored. The shrink item isn't a continuous spell effect. The spell effect only becomes active when it's activated again, taking the object as is. As long as the lid is closed the space inside the chest should be included as part of the chest, with objects placed inside or removed a part of that chest as is."

(this is the type of arguments my players make)

What's the best way to handle this permanent shrink item chest?

The answer also affects every other application in this regard: a spare quiver, a waterskin, coinpurse, cloak with pockets, an object repaired with new parts, those cumbersome saddlebags, or even a wizard's spell book adding new spells

Answer 1

The Shrink Item spell has a special rule when used with the Permanency spell in its last paragraph that reads:

Shrink item can be made permanent with a permanency spell, in which case the affected object can be shrunk and expanded an indefinite number of times, but only by the original caster.

So you can shrink/unshrink a Permanent Shrink Item enchanted chest i indefinitely as long as you are the original caster.

However nothing in Shrink Item allows the chest to transfer this effect to contents not present when the spell was cast, so without a lenient DM this cannot be used to fill a chest with contents and then shrink it all down.

It is still a very convenient method of transporting multiple chests for when they are needed.

Answer 2

Secret chest (Leomund's secret chest in the PHB) has no change in storage functionality when shrunken via shrink item regardless of permanency. However, this is not due to shrink item. Instead, it is due to the text of secret chest which states:

The chest can contain up to 1 cubic foot of material per caster level (regardless of the chest’s actual size, [emphasis added] which is about 3 feet by 2 feet by 2 feet).

Although the chest has a default size which is given, that is immaterial to the storage capabilities of the chest, per the rules given above.

Likewise, if you were to cast enlarge person on someone carrying a secret chest, storage capabilities of the chest would be unchanged even though the size of the container was made larger along with the person's other possessions.

However, if you were dealing with any other chest that lacked a similar property, shrink item only shrinks one item, not a volume, though the maximum size of the item is governed by caster level. As such, it cannot be used to shrink both a chest and its contents. Each individual item must be shrunken. So in the case of an ordinary chest, only items that can fit into the shrunken volume on their own may be inside the chest when it either shrinks or is already shrunk. Permanency again has no effect because it doesn't change the target of shrink item to be more than one item.

Answer 3

After perusing other materials I came across a ruling that may provide some evidence to answer this question.

The premise that a spell made permanent only interacts with the object as it was when the spell was first cast isn't always true.

Consider the way the spell invisibility interacts with objects placed inside an invisible object:

d20srd: Invisibility

Items picked up disappear if tucked into the clothing or pouches worn by the creature.

This is significant as it demonstrates that an object under the effect of a spell can affect new objects placed inside that weren't present at the time of casting. Items placed inside the chest may also be affected by the shrink item spell when commanded. 🤔

The invisibility spell doesn't offer an explanation as to why it does this, and player might speculate a logical explanation, but the truth is we don't know. As far as it's written, it just does.

Since the effects of an invisibility spell can affect objects placed inside a permanently invisible chest, it lends credence that the effects of a shrink item spell can also affect objects placed inside a permanent shrink item chest.

Answer 4

Restoring the shrunken object to its normal size and composition ends the spell.

Permanency doesn't allow you to reshrink items. It just extends the duration of the original spell. If you restore the item(s) to their full size, the spell ends, as per the spell text.

Even if it did allow reshrinking, it would be for the original targets of the spell. Not 'whatever is put into the chest'. Those are not targets of the original spell and are unaffected by the spell, even a houseruled version that allows at-will unshrinking and reshrinking. If you're looking for a spell that allows a chest to shrink any items placed into it as it shrinks down, at will for a duration, that sounds like a completely different spell, a magic item, or just a bag of holding.