# Retail item useability and AutoWear rejection

Date: 2026-07-23

## Retail anchors

- `ItemUses::ItemUses @ 0x004FCCB0`
- `ItemUses::IsUseable @ 0x004FCCC0`
- `PublicWeenieDesc::Reset @ 0x005ACC70`
- `PublicWeenieDesc::UnPack @ 0x005AD470`
- `ItemHolder::DetermineUseResult @ 0x00588460`
- `ItemHolder::UseObject @ 0x00588A80`
- `CPlayerSystem::UsingItem @ 0x00562F70`
- `CPlayerSystem::AutoWearIsLegal @ 0x0055EF40`
- `CPlayerSystem::AutoWear @ 0x005601C0`
- `ACCWeenieObject::GetObjectAtLocation @ 0x0058CE00`

The named pseudo-C is the behavioral oracle. The matching v11.4186 binary was
also inspected because an older project note interpreted
`ItemUses::IsUseable` as a nonzero test. The actual instructions are:

```text
004fccc0  mov eax,[ecx]
004fccc2  not eax
004fccc4  and eax,1
004fccc7  ret
```

Therefore the method tests only `USEABLE_NO` (bit zero). A zero-valued
`ITEM_USEABLE` is usable; `USEABLE_NEVER_WALK` is a movement modifier and does
not make the object unusable. The literal AutoWear rejection at `0x007CC868`
is:

```text
You must remove your %s to wear that
```

The staged ACE, holtburger, and ACViewer reference directories are currently
empty in this checkout. Their established roles were still checked: ACE owns
the authoritative use/wield outcome, while the two client references do not
replace the retail UI-side legality and notice oracle. No server behavior is
being inferred or moved client-side here.

## Pseudocode

```text
ItemUses.IsUseable():
    return (useableBitfield & USEABLE_NO) == 0
```

`PublicWeenieDesc::Reset` zeros the useability field. `UnPack` replaces it only
when the optional useability word is present. Consequently an absent wire word
and an explicitly packed zero both have retail `USEABLE_UNDEF` value zero and
both pass `IsUseable`.

For a direct-use item, `ItemHolder::UseObject` then sends
`CM_Inventory::Event_UseEvent`, increments the UI busy count, and calls
`CPlayerSystem::UsingItem`. `Event_UseEvent` itself is the network send
(`0xF7B1/0x36`); the latter function handles local pickup/wield/container
presentation. Therefore neither an owned item nor a world object may be held
behind a client-side movement completion. ACE owns the authoritative approach
chain.

```text
AutoWearIsLegal(itemId, out alreadyWorn, silent):
    alreadyWorn = false

    if player is not ready for an inventory request:
        return false

    item = GetWeenieObject(itemId)
    if item is null:
        return false
    if (item.validLocations & 0x08007FFF) == 0:
        return false

    if (item.priority & playerSystem.clothingPriorityMask) == 0:
        return true

    player = GetWeenieObject(playerId)
    if player contains item at a worn location:
        alreadyWorn = true

    if not silent:
        if alreadyWorn:
            display "The <item appropriate name> is already being worn"
        else:
            occupied = playerSystem.inventoryMask & item.validLocations
            blocker = player.GetObjectAtLocation(occupied, item.priority)
            if blocker exists:
                display "You must remove your <blocker appropriate name> to wear that"

    return false
```

```text
AutoWear(itemId, out alreadyWorn, silent):
    if not AutoWearIsLegal(itemId, alreadyWorn, silent):
        return false

    item = GetWeenieObject(itemId)
    if item exists:
        item.UIAttemptWield(item.validLocations)
    return true
```

## Port boundary

- `ItemUseability.IsUseable` is the one Core implementation of the low-bit
  rule. Toolbar enablement, item activation, and world interaction consume it.
- `ItemInteractionController` remains the shared double-click and toolbar-hand
  path. A zero-valued carried gem such as Blackmoor's Favor therefore emits the
  ordinary Use request directly from its inventory identity; it is never sent
  through the world-approach query. ACE remains authoritative for its spell
  and consumption outcome.
- `SelectionInteractionController` sends accepted ordinary Use immediately for
  both owned and spatial objects. It does not install speculative local
  TurnToObject/MoveToObject movement; ACE's authoritative movement packets use
  the shared retail `MoveToManager`.
- `AutoWieldController` remains the shared inventory/paperdoll equip owner. It
  resolves AutoWear blockers from `ClientObjectTable`'s retail-ordered
  equipment projection and emits the retail literal through system chat.
- Weapon replacement is unchanged. Retail automatically moves primary weapon,
  incompatible shield, and incompatible ammunition blockers, while AutoWear
  rejects overlapping clothing/armor and tells the player what to remove.