Are there non-weapon, non-backpack items? Do the special items go somewhere, or are they generally held?
The example covers in broad strokes what you want (or seems to, although I didn’t test extensively). #3 should be caught if you’re using “try taking X” rules for your other actions. For an example of this, try eating the box of chocolates in the example if your backpack is full. (I would argue against this particular instance as a player, given that you’d have to drop something, pick up the chocolate, eat the chocolate, and then pick the thing up again, so tweakage may be advised.)
[code]“Inventory Management” by Gravel
Include Plurality by Emily Short.
Section - The Backpack
The player is wearing a container called a backpack.
Instead of taking off, dropping the backpack:
say “You can’t bring yourself to leave behind your trusty backpack!”
Definition: a backpack is loaded if the number of things contained by it is greater than 7.
After taking a storable thing (called the target) (this is the stow storables rule):
now the target is in the backpack;
say “You put [the target] in your backpack.”;
Check taking something enclosed by the backpack:
say “You can do whatever you need to with that while it’s in your pack.” instead.
Check dropping something enclosed by the backpack:
now the player is holding the noun;
try dropping the noun;
if the player is holding the noun:
now the noun is in the backpack;
say “Unable to drop [the noun], you reinsert [it-them] into your pack.” instead;
do nothing instead.
Section - Storable Things
A thing is either storable or not storable. A thing is usually storable.
Check taking a storable thing when the backpack is loaded:
say “Your backpack is stuffed to bursting already.” instead.
The dagger, spear, and sword are in the Equipment Room.
A box of chocolates is in the Equipment Room. A box of chocolates is edible.
Section - Weapons
A weapon is a kind of thing. The dagger, the spear, and the sword are weapons. A weapon is usually not storable.
Check taking a weapon (this is the weapon limitation rule):
if the player encloses more than one weapon:
say “You can only carry two weapons at a time.” instead.
Section - Plot Items
A plot item is a kind of thing. The Wand of Opening is a plot item in the Equipment Room. A plot item is never storable.
Section - Release
The Equipment Room is a room. A statue, a coin, a duck, some junk, a balloon, a can, a bottle, a glass, and an old phone are in the Equipment Room.
Instead of dropping the glass, say “It might break!”
Things in containers automatically separate out in inventory, so it’s always going to look sort of like:
Assuming you do implement the pouch as a container. You might also look at “Persephone” as far as inventory management goes.
You’re going to need rules to address the fact that you’ll usually be manipulating stuff from your pack; you can see a kludgy workaround for the drop action above. Fortunately, there’s not too many of these.