Cookbook

Ready-made rule sets. Config keys are in Server config, tags in Tags and exclusive sets.

Make switching cost 1 lapis

[toggle]
cost_type = "ITEM"
cost_amount = 1
cost_item = "minecraft:lapis_lazuli"

Make Sharpness and Fire Aspect switchable

[exclusivity]
extra_groups = ["minecraft:sharpness, minecraft:fire_aspect"]

They now conflict for Adjustability: a sword can hold both, one active at a time.

Let Infinity and Mending stack

[exclusivity]
compatible = ["minecraft:infinity, minecraft:mending"]

They no longer conflict for Adjustability, so the anvil puts both on a bow, both active.

Mining switches cost lapis, armor switches are free

[toggle]
group_costs = [
    "#minecraft:exclusive_set/mining = ITEM 1 minecraft:lapis_lazuli",
    "#minecraft:exclusive_set/armor = NONE",
]

Keep Infinity and Mending apart

data/adjustability/tags/enchantment/not_combinable.json:

{
  "replace": false,
  "values": ["minecraft:infinity"]
}

At most two Protections per armor piece

[anvil]
max_conflicts_per_component = 2

Only netherite tools are adjustable

[items] in the server config:

[items]
mode = "ALLOWLIST"

and data/adjustability/tags/item/adjustable.json in your datapack:

{
  "values": [
    "minecraft:netherite_pickaxe",
    "minecraft:netherite_axe",
    "minecraft:netherite_shovel",
    "minecraft:netherite_hoe",
    "minecraft:netherite_sword"
  ]
}

Hardcore: expensive and slow

[anvil]
dormant_cost_per_level = 3
max_dormant_per_item = 2

[toggle]
cost_type = "XP_LEVELS"
cost_amount = 2
cooldown_ticks = 200
allow_in_world_cycle = false

An advancement for your pack

The adjustability:switched trigger fires on every switch. All its conditions are optional: none (true: only switches to none, false: only to an enchantment), min_switches (the player's total switches, including this one) and holds (enchantments, a list or a #tag, that the item must all hold afterwards, active or dormant). Put it in data/<your pack>/advancement/:

{
    "parent": "adjustability:root",
    "criteria": {
        "trident_master": {
            "trigger": "adjustability:switched",
            "conditions": {
                "holds": ["minecraft:riptide", "minecraft:loyalty", "minecraft:channeling"],
                "min_switches": 10
            }
        }
    },
    "display": {
        "icon": { "id": "minecraft:trident" },
        "title": "Weather Permitting",
        "description": "Switch a trident with Riptide, Loyalty and Channeling, ten switches in"
    }
}

Uninstall cleanly

Before removing the mod, run /adjustability flatten @a with everyone online. Items keep their active enchantments; switched-off ones come back on, the other dormant ones are removed. What it doesn't reach (chests in the world, shulker boxes) is harmless: see Uninstalling.