Quote from Dertian >>

What requirements would one use to "restock" it? It's too good to just let it go to waste when empty.

Like using a profession to create the patch, using up the desired item to "store" mundane item, and exhaust a spell slot every day for some days, to create a new patch.

 Probably just regular magic item crafting rules, maybe let them make it with a gold or two discount on materials because they have a head start with the empty cloak.

Quote from HeathSmith >>

so, adding up all the PHB prices for items and taking them by their probability of occurring, you get - on average - a total of 1,903 gold worth of items...for a product that costs 200 gp to purchase per XGE.  Hmm

Quote from Unruly_Cow >>

This can theoretically be bought for between 100 and 600 gold. Multiple patches give you money or expensive items. It could be quite profitable to buy one of these.

 

 If you still have whatever notes you took while mathing this, would you be willing to post your work here? I'm somewhat curious as to the math of this.

Quote from b1oody67 >>

how much HP does the iron door have?

 According to DMG, Iron things have AC of 19, and a 10 by 10 Window is Large, 10 by 10 being max door dimensions, so I'll go off that here. That has 5 (1d10) HP if Fragile, 27 (5d10) if Resilient.

Resilient feels like the better fit I would say.

Quote from Dartagnan_Galochio >>

 If you still have whatever notes you took while mathing this, would you be willing to post your work here? I'm somewhat curious as to the math of this.

 here you go, there's several assumption in here, but this is what I came up with

I like to add this as a hidden magic item while my players are shopping that the shop keeper doesn't know what it is. If they do find it and investigate I make them notice one of the patches is hanging on by a single thread. The patch falls(Roll 1d100). That player then gets yelled at by the shop owner, "HEY! NO PETS ALLOWED!!!"  for two slobbing Mastiffs suddenly appearing his store and gets thrown out with a free cloak and two friendly puppers. ;-)

The robe is part of a ghost. As it needs a previous edition spell shrink item spell.  Look up the spell and you will see how it would work.

Why they removed the spell I am not shure.

this is like asking if a beholder is technically prone 

replying to the guy who asked if the patches are extradimensional spaces

No idea either, you ever figure this out?

and plus it could be the dm's choice. If your chaotic Evil the dm might make the creature aggressive. 

is it possible to hand make the patches using weaver's tools? (beginner here)

Does this thing have a constant weight or does it's weight change based on the contents?

i just got one in a game im playing, DM rolled the items and got like 4 sets of gemstones plus 1 bag of gold, very profitable for me and i only paid 50 for it. big win

The D&D Beyond character sheet has a HUGE problem with this item. Each patch adds the weight of what it turns into to the weight of the robe. So my gnome is walking around carrying 448 pounds! Those 12 foot long rowboats are killing me.

Of course he's not walking around. I can only presume that he died of exhaustion the moment he put on the robe.

Before anyone asks, yes, I tried to customize the weight. The sheet won't allow it. So it looks like we're going to have to handwave away the weight issue. It's a pity the software can't take this into account, though.

Why is this not available on D&D Beyond? It's listed as being on pg 195 of the basic rules, but it isn't. 

Ugh I can't figure out how to add patches under 'customize'.  Is such a thing even doable?  Any walkthrough would be appreciated.

I made the Robe a custom container, and added each patch as a custom item in that container - with each patch as a custom item named for what it becomes and the weight added in the notes for that item (but NOT in the weight, which I left as zero). It works well. It was a little tedious, but until DDB gets it worked out properly it's the best option I could find.

Does the window work like the iron door? Magically attaching itself in place? If so, would it create a space for a window if there previously wasn’t one? Just wanting to make sure I understand what it’s supposed to do. 

Curious why under either notes and/or item tags an entry for college/school of magic is not given. What would Detect Magic show?

I don't know for sure, but I think it would probably be transmutation? It does say that "...detach[ing] one of the patches, caus[es] it to become the object or creature it represents". Just looking through D&D Beyond's magic item list, quite a few of the items don't have a particular school of magic listed with them. I guess some can be obvious if they allow you to cast a spell of a specific school or have effects that imitate one of those spells. As far as the robe of useful items goes, I'd say transmutation because the patches themselves are turning into the objects.

If you wanted to add a level of mystery to this item, you could have a few of the patches be completely  nondescript/hidden without a decent investigation check to figure out where/what they are. If you are a generous DM and a patch is pulled at random in a time of need, you could simply have it become what the party needs in that moment. 

Make sure you are under the robe of useful items when you try to add items, I selected customize and it should show - 'Custom Item 1' and then gave it a name like "Patch - Rowboat". The item shows up under the robe.