Abilities — import "abilities" ​

Named item abilities on per-player cooldowns. on_item_use binds a handler to a custom item id and click side; with_cooldown wraps a handler so it fires at most once per player per cooldown window, showing an actionbar countdown while it waits.

import "abilities"

item "aspect_of_the_end" {
    material: "DIAMOND_SWORD"
    name: "<blue>Aspect of the End"
    rarity: rare
    glint: true
}

command "kit-setup" {
    execute {
        on_item_use("aspect_of_the_end", "right", with_cooldown(3.0,
            function(user: Player, held: Item) {
                send "<aqua>Instant Transmission! Whoosh." to user
            }))
        send "<gray>Aspect ability registered." to sender
    }
}

Exports ​

Both take a handler — a function(user: Player, held: Item) lambda. Because lambdas are first-class values, with_cooldown returns a wrapped handler you hand straight to on_item_use.

on_item_use(item_id, filter, handler) ​

Registers handler to run when a player uses the custom item with id item_id. filter is "left", "right", or "any", kept for parity with the item on_click sugar. Registering again for the same id + filter replaces the previous handler. The handler receives the acting Player and the Item in hand — read its tags to drive stat formulas:

import "abilities"

command "wire" {
    execute {
        on_item_use("aspect_of_the_end", "right",
            function(user: Player, held: Item) {
                set dmg to held.tags.damage otherwise 0
                send "<aqua>Transmission for ${dmg} damage!" to user
            })
    }
}

item "aspect_of_the_end" { material: "DIAMOND_SWORD" tags { damage: 100 } }

with_cooldown(seconds, handler) ​

Wraps a (Player, Item) handler with a per-player cooldown of seconds seconds and returns a handler of the same shape. When a player is still cooling down, the wrapped handler sends an actionbar countdown and does nothing else; otherwise it runs the inner handler and arms the cooldown. Each with_cooldown call owns an independent window, so two wrapped abilities never share a timer:

import "abilities"

command "wire" {
    execute {
        // a 5-second ability and a 1-second ability, independent cooldowns
        on_item_use("blink_staff", "right", with_cooldown(5.0,
            function(user: Player, held: Item) {
                send "<light_purple>Blink!" to user
            }))
        on_item_use("spark_wand", "right", with_cooldown(1.0,
            function(user: Player, held: Item) {
                send "<yellow>Spark!" to user
            }))
    }
}

item "blink_staff" { material: "BLAZE_ROD" }
item "spark_wand" { material: "STICK" }

How it's built ​

addons/abilities.sw is about fifty lines of SwoftLang and uses three patterns from the guide:

• A module-level association chain (module vars) stores handlers and cooldown deadlines by string key — the same closure-chain registry trick the retired NPC addon used before it became a runtime. on_item_use prepends a "use:<id>:<filter>" -> handler entry; with_cooldown reads and writes "cd:<slot>:<uuid>" deadlines.
• A self-counted tick clock. An every 1 ticks block increments a module counter, so the addon measures cooldown windows in ticks (20 per second) without needing a wall-clock builtin.
• A single generic listener. One PlayerUseItem handler reads event.custom_id and dispatches to every registered filter for that item — the one place all custom-item uses flow through.

// the single generic surface: every custom-item use flows through here
event PlayerUseItem {
    execute {
        set id to event.custom_id otherwise ""
        // dispatch 'id' to the handlers registered for it (addon internals)
    }
}

The same shape — a registry of handlers, a tick clock, one dispatch listener — fits any "named action with bookkeeping".