#Index & Inventory
The Index records discovered species and zone completion. The backpack stores pets and eggs; the pet bag shows animals currently equipped on the base.

#Discovery and zone rewards
Species entries define IndexCash and IndexSpeed. Machine collection helpers calculate zone completion from the zone's pet list and the Discovered table. A completed zone can grant its configured reward once.
The Index button's badge represents claimable zone rewards. It is calculated at startup instead of displaying a fixed template value.
#Bat skins
Claiming a qualifying zone reward unlocks its cosmetic bat. Click its Index icon to equip it; choosing it again can return to the default bat. The mapping is in MachineShared.BatSkins.
Zones 1, 2, 3, 4, 5, 7, 8 and 9 have bat skins. Zones 6 and 10 have no skin mapped in this build. Electric Hammer is not part of this reward flow.
#Backpack and hotbar

| Action | Result |
|---|---|
| Unequip a base pet | Moves it to the hotbar when room is available; otherwise the backpack |
| Activate a pet tool in your own base | Places the pet on the pen |
| Open backpack with I | Shows pets, eggs, search and hotbar slots |
| Click a hotbar pet while backpack is open | Returns it to the backpack |
| Select a backpack pet, then Hotbar | Moves it into a free pet-tool slot |
| Sell | Removes the pet and pays its configured sell value |
The hotbar has ten slots including pickaxe and bat, leaving eight pet slots. A backpack pet must not also be marked Placed or Hotbar. Keep those states consistent when adding new inventory actions.
#Visible collection scope
The Index shows the ten actual map zones and an Unlocked: x/86 total. The former extra 0/5 fusion-only card has been removed; fusion pets and their recipes still exist. Zone-card progress is centered, with the bat reward at the right. Detail colors follow pet rarity.