Terminal Upgrade Cards

ITerminalUpgradeCard is a 1.21.1-only API. It does not exist in the inspected 1.20.1 codebase.

1.20.1 does already inject terminal UI scaffolding through MEStorageMenuMixin and MyoSlotSemantics, including the floating side panel and placeholder upgrade slot semantics. What it does not ship is the card interface, card lifecycle callbacks, or persistent upgrade storage.

Purpose

It marks items that can be inserted into terminal upgrade slots and receive lifecycle callbacks while installed in an AE2 terminal.

Lifecycle hooks

public interface ITerminalUpgradeCard {
    default void onTerminalOpen(MEStorageMenu menu, ItemStack stack) {}
    default void onTerminalClose(MEStorageMenu menu, ItemStack stack) {}
    default void onTerminalTick(MEStorageMenu menu, ItemStack stack) {}
}

Authoring expectations

• upgrade cards should be non-stackable
• callbacks are server-side terminal lifecycle hooks
• only override the hooks your card actually needs

Example

public class MyUpgradeCardItem extends Item implements ITerminalUpgradeCard {
    @Override
    public void onTerminalOpen(MEStorageMenu menu, ItemStack stack) {
        // Apply one-time behavior when the terminal opens.
    }

    @Override
    public void onTerminalTick(MEStorageMenu menu, ItemStack stack) {
        // Run while the card is installed in an open terminal.
    }
}

Persistent storage

PlayerUpgradeContainer stores upgrade slot contents in player persistent data.

Important details from the inspected implementation:

• slot count is fixed at 5
• storage is keyed per terminal-specific storage key
• legacy NBT keys are migrated when found
• the old shared terminal_upgrades payload is migrated into the first terminal opened after the update

See Upgrade Storage for the full storage-key, migration, and menu-mixin flow.

Built-in example item

The 1.21.1 tree contains a DiamondUpgradeCardItem test item. It is registered only outside production builds and grants a diamond when the terminal opens.

That makes it a dev example, not a production-facing gameplay feature.

Related helpers

The same codebase also provides TerminalUpgradeHelper so addon code can inspect installed cards without manually walking the slot list.