Ultimate Mod Additions 1.21.1 Wiki EN

Ultimate Mod Additions Wiki (English)

The examples on this page use the namespace nadien_teaks:. Use your own — the mod never looks at the namespace, only at the folder.

Index

Section	What it covers
Datapacks	Where the files go, how they reload, shared types
Difficulties	`uma/difficulty` — mob scaling
Mob rules	`uma/mob_rules` — what each mob drops and how hard it is
Loot bags	`uma/loot_bags` and `uma/loot_bag_additions`
Trades	`uma/trades` — the exchange stand
Currency	The nine denominations and how they work
Coliseum	The dimension, the amphitheatre, the portal and the key
KubeJS	The `UMA` binding and all of its methods
Commands	`/uma` and `/ums`
Configuration	The config TOML
Full example	One file of every kind, in JSON and in KubeJS

What the mod adds

Thing	Id	What it does
Coliseum dimension	`ultimatemodadditions:coliseum`	A dimension of its own holding a Roman amphitheatre the mod builds by itself. Mobs inside it are scaled by the active difficulty and drop coins and bags.
Coliseum portal	`ultimatemodadditions:coliseum_portal`	The block that fills a lit crying obsidian frame. Walk into it to travel; it checks the requirement per player. It cannot be crafted or picked up — it appears when a frame is lit.
Coliseum key	`ultimatemodadditions:coliseum_key`	Lights a portal. Right-click each of the four corners of a crying obsidian frame; on the fourth the key is consumed. Craftable, never buyable.
Exchange stand	`ultimatemodadditions:exchange_stand`	The shop block. Right-click to open the offer list, which is filled from `uma/trades/`. Pays with any mix of coins and returns change.
Coins	`coin_10` … `coin_20000`	Nine denominations of money. Right-click to merge all your loose change into the fewest coins, sneak + right-click to break one into smaller ones. Mobs drop them.
Loot bags	`loot_bag_common` … `loot_bag_enchantment`	Eight rarities of container. Right-click to open one, sneak to open the stack. What comes out is defined in `uma/loot_bags/`.

Datapacks

Where the files go

Everything lives under data/<any_namespace>/uma/…. The namespace does not matter, use your own. Three places work:

a normal datapack, in world/datapacks/nadien_teaks/data/nadien_teaks/uma/…
the KubeJS folder, in kubejs/data/nadien_teaks/uma/…
the mod itself, if you are building it

They reload with /reload. No restart needed.

Folders

Folder	What it defines
`uma/difficulty/`	Mob scaling profiles
`uma/mob_rules/`	Which mob uses which difficulty, and what it drops
`uma/loot_bags/`	The contents of each bag
`uma/loot_bag_additions/`	Extra drops added to bags that already exist
`uma/trades/`	Exchange stand offers

Shared types

Integer range

Wherever this page says range, you can write a plain number or an object:

"count": 3
"count": { "min": 1, "max": 4 }

`match` — item and block filter

"match": {
  "items": ["minecraft:diamond_pickaxe"],
  "tags": ["c:tools/pickaxe"],
  "blocks": ["minecraft:stone"],
  "block_tags": ["minecraft:mineable/pickaxe"],
  "regex": ["^minecraft:.*_ore$"],
  "exclude": ["minecraft:bedrock"]
}

items and tags are checked against items; blocks and block_tags against blocks.
regex runs on the full id (minecraft:diamond) and is only consulted when nothing matched by list or tag.
exclude beats everything else.

`entity` — entity filter

"entity": {
  "entities": ["minecraft:zombie"],
  "tags": ["minecraft:skeletons"],
  "regex": ["^minecraft:.*_zombie$"],
  "categories": ["monster"],
  "exclude": ["minecraft:villager"],
  "boss": true,
  "baby": false
}

categories accepts monster, creature, ambient, water_creature, axolotls, underground_water_creature, water_ambient and misc.
boss looks at the c:bosses tag.
If you leave entities, tags and regex empty it matches any entity that passes the remaining filters.

`components`

Any entry that hands out an item accepts components, using the 1.21 component format:

{
  "item": "minecraft:enchanted_book",
  "components": {
    "minecraft:stored_enchantments": { "levels": { "minecraft:mending": 1 } }
  }
}

Difficulties

data/<namespace>/uma/difficulty/<id>.json

A difficulty profile is a bundle of multipliers applied to a mob when it spawns. easy, normal, hard and nightmare ship with the mod.

{
  "name": "Hard",
  "health_multiplier": 2.5,
  "damage_multiplier": 1.75,
  "speed_multiplier": 1.1,
  "armor_bonus": 4.0,
  "armor_toughness_bonus": 2.0,
  "knockback_resistance": 0.2,
  "follow_range_bonus": 12.0,
  "experience_multiplier": 2.0,
  "coin_multiplier": 2.0,
  "bag_chance_bonus": 0.05,
  "extra_loot_rolls": 1,
  "glowing": false,
  "effects": [
    { "effect": "minecraft:strength", "amplifier": 0, "duration": -1, "chance": 1.0 }
  ],
  "equipment": {
    "mainhand": { "item": "minecraft:netherite_sword", "chance": 0.35, "drop_chance": 0.02 }
  }
}

Fields

Field	Type	Default	What it does
`name`	string	—	Display name, optional
`health_multiplier`	double	1.0	Multiplies max health
`damage_multiplier`	double	1.0	Multiplies attack damage
`speed_multiplier`	double	1.0	Multiplies movement speed
`armor_bonus`	double	0.0	Adds armor
`armor_toughness_bonus`	double	0.0	Adds armor toughness
`knockback_resistance`	double	0.0	Adds knockback resistance (0–1)
`follow_range_bonus`	double	0.0	Adds follow range
`experience_multiplier`	double	1.0	Multiplies dropped experience
`coin_multiplier`	double	1.0	Multiplies dropped coins
`bag_chance_bonus`	double	0.0	Adds to the loot bag chance
`extra_loot_rolls`	int	0	Extra loot rolls
`glowing`	boolean	false	Leaves the mob glowing
`effects`	list	empty	Permanent or timed potion effects
`equipment`	object	empty	Gear per slot

`effects`

{ "effect": "minecraft:strength", "amplifier": 0, "duration": -1, "chance": 1.0 }

duration: -1 is permanent. chance runs from 0 to 1.

`equipment`

The keys are slots: mainhand, offhand, head, chest, legs, feet.

"equipment": {
  "head":  { "item": "minecraft:netherite_helmet", "chance": 0.5, "drop_chance": 0.01 },
  "chest": { "item": "minecraft:netherite_chestplate", "chance": 0.5 }
}

Field	Default	What it does
`item`	required	What gets equipped
`count`	1	Amount
`chance`	1.0	Chance the mob carries it
`drop_chance`	0.085	Chance it drops on death
`components`	—	Item components

How the difficulty is chosen

If the matching mob rule carries difficulty, that profile is used.
If it carries inline_difficulty, that inline profile is used.
Otherwise the Coliseum's active difficulty is used (/uma difficulty set).

See Mob rules.

Mob rules

data/<namespace>/uma/mob_rules/<id>.json

They decide which difficulty each mob uses and what it drops when it dies. They are checked from highest to lowest priority; the first one that matches wins.

{
  "priority": 0,
  "match": { "categories": ["monster"] },
  "dimensions": ["ultimatemodadditions:coliseum"],
  "difficulty": "ultimatemodadditions:hard",
  "replace_vanilla_drops": true,
  "experience_multiplier": 2.0,
  "stop_matching": false,
  "drops": [
    { "item": "minecraft:diamond", "count": { "min": 1, "max": 3 }, "chance": 0.5, "looting_bonus": 0.1 },
    { "loot_table": "minecraft:chests/simple_dungeon", "chance": 0.1 },
    { "bag": "ultimatemodadditions:epic", "chance": 0.02 }
  ],
  "coins": [ { "tier": "500", "count": { "min": 1, "max": 3 }, "chance": 0.5 } ],
  "bags":  [ { "bag": "ultimatemodadditions:common", "chance": 0.06 } ]
}

Fields

Field	Type	Default	What it does
`priority`	int	0	Higher is checked first
`match`	entity filter	anything	Which mobs it applies to
`dimensions`	list of ids	empty = all	Which dimensions it applies in
`difficulty`	id	—	Difficulty profile to use
`inline_difficulty`	object	—	An inline profile instead of `difficulty`
`replace_vanilla_drops`	boolean	false	Wipes the mob's vanilla loot
`drops`	list	empty	Custom loot
`coins`	list	empty	Coins it drops
`bags`	list	empty	Bags it drops
`experience_multiplier`	double	1.0	Multiplies dropped experience
`stop_matching`	boolean	false	Stops the search even if nothing applies

The filter goes in match and uses the entity filter format.

`drops`

Every entry can hand out an item, a loot table or a bag.

Field	Default	What it does
`item`	—	Item to drop
`count`	1	Amount (range)
`chance`	1.0	Chance, 0 to 1
`weight`	1	Only used inside bags
`looting_bonus`	0.0	Added to `chance` per level of Looting
`components`	—	Item components
`loot_table`	—	Rolls a whole loot table
`bag`	—	Hands out a bag by id

If bag is present, item is ignored.

`coins`

{ "tier": "500", "count": { "min": 1, "max": 3 }, "chance": 0.5 }

tier is the denomination: "10", "20", "50", "100", "200", "500", "1000", "10000" or "20000". The old names bronze, silver and gold are still accepted and mean 10, 100 and 1000.

The final amount is multiplied by the difficulty's coin_multiplier.

`bags`

{ "bag": "ultimatemodadditions:common", "count": 1, "chance": 0.06 }

The difficulty's bag_chance_bonus is added to chance.

Loot bags

`uma/loot_bags/<id>.json`

Every file is one bag. Make as many as you like: tier decides which of the eight items it rides on, and with that its texture and rarity.

{
  "name": "Epic Bag",
  "tier": "epic",
  "color": 12213503,
  "sort_order": 30,
  "rolls": { "min": 3, "max": 5 },
  "unique_rolls": true,
  "announce": false,
  "open_sound": "ultimatemodadditions:loot_bag_open",
  "guaranteed": [
    { "item": "ultimatemodadditions:coin_500", "count": { "min": 1, "max": 3 } }
  ],
  "entries": [
    { "item": "minecraft:diamond_block", "count": 1, "weight": 16 },
    { "bag": "ultimatemodadditions:enchantment", "count": 1, "weight": 8 }
  ]
}

Field	Type	Default	What it does
`name`	string	—	Display name of the bag
`tier`	string	`common`	Rarity, see the table below
`rolls`	range	1	How many entries get rolled
`guaranteed`	list	empty	Fixed loot, always drops
`entries`	list	empty	Random pool, rolled by `weight`
`unique_rolls`	boolean	false	Stops the same entry rolling twice
`color`	int	0xFFFFFF	Decimal colour for the name
`open_sound`	id	—	Sound played when opened
`announce`	boolean	false	Tells the whole server when it is opened
`sort_order`	int	0	Order in JEI

Entries use the same format as the drops of a mob rule, including loot_table and bag for nested bags.

Tiers

`tier`	Base item	Buyable at the stand
`common`	`loot_bag_common`	yes
`uncommon`	`loot_bag_uncommon`	yes
`epic`	`loot_bag_epic`	no
`mythic`	`loot_bag_mythic`	no
`legendary`	`loot_bag_legendary`	no
`omega`	`loot_bag_omega`	no
`food`	`loot_bag_food`	no
`enchantment`	`loot_bag_enchantment`	no

rare is still accepted as an alias of epic for older datapacks.

`uma/loot_bag_additions/<id>.json`

For adding loot to bags that already exist without rewriting them. They are applied after every bag has loaded, so they work on the mod's bags, another datapack's, or KubeJS ones.

{
  "bag": "ultimatemodadditions:common",
  "bags": ["ultimatemodadditions:uncommon"],
  "tiers": ["legendary", "omega"],
  "entries": [
    { "item": "minecraft:copper_ingot", "count": { "min": 2, "max": 6 }, "weight": 12 }
  ],
  "guaranteed": [
    { "item": "ultimatemodadditions:coin_50", "count": 1 }
  ],
  "replace": false
}

Field	Default	What it does
`bag`	—	One specific bag
`bags`	empty	Several specific bags
`tiers`	empty	Every bag of those rarities; `["all"]` reaches all of them
`entries`	empty	Added to the random pool
`guaranteed`	empty	Added to the fixed loot
`replace`	false	When `true`, wipes the previous contents before adding

bag, bags and tiers add up: the addition applies to every bag that matches any of the three.

Opening them

Right-click opens one. Sneak opens the whole stack. The loot goes to the inventory and whatever does not fit drops on the floor.

Trades

data/<namespace>/uma/trades/<id>.json

These are the offers of the exchange stand (ultimatemodadditions:exchange_stand).

{
  "name": "Uncommon Bag",
  "category": "bags",
  "sort_order": 20,
  "price": 700,
  "cost": [ { "item": "minecraft:emerald", "count": 4 } ],
  "result": { "bag": "ultimatemodadditions:uncommon", "count": 1 },
  "stock": -1,
  "enabled": true
}

Field	Type	Default	What it does
`name`	string	the result's name	Label in the list
`category`	string	`general`	Free-form grouping
`price`	int	0	Price in money
`cost`	list	empty	Specific items that must also be paid
`result`	object	required	What is handed over
`sort_order`	int	0	Order in the list
`stock`	int	-1	Reserved, -1 is unlimited
`enabled`	boolean	true	When `false` the offer does not show up

`price` and `cost`

price is paid with any mix of coins and gives change back. cost demands exact items. Both can be used at once.

"cost": [ { "item": "minecraft:emerald", "count": 4 } ]

`result`

"result": { "item": "minecraft:golden_apple", "count": 1 }
"result": { "bag": "ultimatemodadditions:common", "count": 1 }

Field	Default	What it does
`item`	—	Item to hand over
`count`	1	Amount
`bag`	—	Hands over a bag by id; beats `item`
`components`	—	Item components

What cannot be bought

The stand rejects certain offers even if you define them, and does not show them in the screen or in JEI:

Bags of rarity epic or above, plus the food and enchantment ones. Only common and uncommon can be bought.
Anything in the ultimatemodadditions:not_purchasable tag. The coliseum key is in there by default.

To allow or block more things, edit that tag from a datapack:

{
  "replace": false,
  "values": ["nadien_teaks:my_item"]
}

The trading screen

Right-click the stand to open it. Clicking a row buys one; shift-clicking buys eight. The top right shows how much money you are carrying.

Currency

The denominations are the Argentine ones: 10, 20, 50, 100, 200, 500, 1000, 10000 and 20000. From 10 to 500 they are mangos, from 1000 to 20000 they are lucas — Argentine slang for "bucks" and "grand", kept in both languages.

Item	Value	Name
`coin_10`	10	10 mangos
`coin_20`	20	20 mangos
`coin_50`	50	50 mangos
`coin_100`	100	100 mangos
`coin_200`	200	200 mangos
`coin_500`	500	500 mangos
`coin_1000`	1000	1 luca
`coin_10000`	10000	10 lucas
`coin_20000`	20000	20 lucas

How they work

There are no conversion recipes. You use them with a coin in hand:

Right-click sweeps every loose coin in the inventory and hands it back as the fewest possible coins, telling you the total.
Sneak + right-click breaks one coin down into the next denominations below it.

Both work whether you are aiming at a block or at the sky.

The price of an exchange stand offer is paid with any combination and gives change back on its own.

In datapacks

Wherever a mob rule asks for a denomination, it is written as text:

"coins": [ { "tier": "500", "count": { "min": 1, "max": 3 }, "chance": 0.5 } ]

The old names bronze, silver and gold are still accepted and mean 10, 100 and 1000.

Coliseum

ultimatemodadditions:coliseum

A dimension of its own with a Roman amphitheatre built by the mod. It is not a flat world: the generator is empty and the arena raises itself the first time the dimension loads.

What is in it

A sand arena with a podium wall around it.
Five tiers of stepped stands.
An outer wall with arches on two decks.
Four gates in a cross.
Lighting and a return portal next to the north gate.

You get in through the portal or with /uma coliseum enter. You always land on the sand.

If you fall outside the amphitheatre the mod puts you back on the arena instead of letting you drop into the void.

The portal

It is built exactly like a nether portal but out of crying obsidian: a rectangular frame, 4×5 counting the frame at minimum (2×3 of opening), up to 23×23. The four corners have to be there.

To light it, right-click each of the four corners with the coliseum key. The mod tells you how many you have done (Corner 2 of 4). On the fourth one a key is consumed and the portal opens. Order does not matter and you can walk around the frame between clicks.

If you break a block of the frame the portal goes out on its own, like a nether one.

Inside the coliseum there is an already-lit portal next to the north gate that takes you back where you came from. That one asks for nothing.

Requirements to pass through

An open portal is not enough: it has to let you through. You need 100 vanilla experience levels, which are not spent.

If you do not meet it the portal rejects you and lists in chat what you are missing and how far along you are. It is checked per player: you cannot drag or push someone in who does not meet it, because each player is checked on entry. Leaving the coliseum asks for nothing.

All of this is changed in [coliseum.portal]:

Option	Default	What it does
`enforce_requirements`	true	When `false` the portal lets anyone through
`required_experience_levels`	100	Experience levels; they are not spent

To test it without grinding: /xp set @s 100 levels.

Arena spawners

When the arena is built, spawners are placed in a ring across the sand, each one on a block of chiselled sandstone. Every spawner carries one mob type, handed out in order from the config list, so all the types you list show up. The one that would land on the spawn point is skipped.

Twelve ship by default: zombie, skeleton, spider, creeper, husk, stray, witch, pillager, blaze, wither skeleton, vindicator and enderman.

/uma spawners list
/uma spawners place
/uma spawners clear

clear removes every spawner in the coliseum, including any you placed by hand. place puts them back according to the config, wiping the previous ones first. Both need permission level 2; list is open to anyone.

To get rid of them for good, set enabled = false in [coliseum.spawners] and run /uma spawners clear.

Spawner config

In [coliseum.spawners]:

Option	Default	What it does
`enabled`	true	Places spawners when the arena is built
`entities`	12 hostile mobs	Which types to use, one per spawner
`count`	12	How many to place; 0 places none
`min_spawn_delay`	200	Shortest wait between batches, in ticks
`max_spawn_delay`	600	Longest wait between batches, in ticks
`spawn_count`	4	How many mobs each batch tries to place
`max_nearby_entities`	8	Stops once this many are already alive nearby
`required_player_range`	24	How close a player has to be
`spawn_range`	6	How far from the spawner mobs can appear

Ids that do not exist are skipped with a warning in the log, so you can list mobs from other mods without breaking anything when they are not installed.

Mobs from these spawners still go through the mob rules and the active difficulty: they come out scaled and drop coins and bags like any other.

The key

ultimatemodadditions:coliseum_key is crafted from a gold ingot, an ender pearl and a gold nugget in a column. It cannot be bought at the exchange stand: it sits in the ultimatemodadditions:not_purchasable tag.

It is used to light the portal and is consumed on completing the four corners. One key opens one portal; after that the portal stays open forever, until you break the frame.

Difficulty

The dimension has an active difficulty that holds for the whole save, and it is used by every mob rule that does not declare its own:

/uma difficulty get
/uma difficulty list
/uma difficulty set ultimatemodadditions:nightmare

See Difficulties and Mob rules.

Rebuilding it

/uma rebuild_arena

Useful if you changed the radius or the height in the config, or if someone wrecked it. Needs permission level 2.

Coliseum config

In [coliseum]:

Option	Default	What it does
`enabled`	true	Turns the dimension on
`build_arena`	true	Builds the amphitheatre on load
`arena_radius`	30	Radius in blocks of the sand floor
`arena_floor_y`	64	Height of the floor
`player_count_scaling`	0.25	How much it scales per player

KubeJS

If KubeJS is installed, the mod adds the global binding UMA. It only works in server scripts (kubejs/server_scripts/), because the data loads together with the datapack. Calling it from startup_scripts or client_scripts means the entry is thrown away when the world loads, and the mod warns you in the log. Entries are re-injected on every /reload, so load order is not something you have to worry about.

The API is made of chained builders. Each one starts with UMA.<type>('id'), you hang methods off it, and it ends with .register(). Nothing happens without .register().

Ids without a namespace resolve to ultimatemodadditions:.

UMA.lootBag('nadien_teaks:mythic')
  .name('Mythic Bag')
  .tier('mythic')
  .rolls(5, 7)
  .guaranteed('ultimatemodadditions:coin_10000', 1)
  .entry('minecraft:netherite_block', 1, 2, 10)
  .register()

The eight builders

Builder	Equivalent to
`UMA.difficulty(id)`	`uma/difficulty/`
`UMA.mobRule(id)`	`uma/mob_rules/`
`UMA.lootBag(id)`	`uma/loot_bags/`
`UMA.bagDrop(id)`	`uma/loot_bag_additions/`
`UMA.trade(id)`	`uma/trades/`

`UMA.difficulty(id)`

UMA.difficulty('nadien_teaks:brutal')
  .name('Brutal')
  .health(10).damage(4).speed(1.2)
  .armor(8).armorToughness(4).knockbackResistance(0.5).followRange(16)
  .experience(3).coins(8).bagChance(0.1).extraRolls(2)
  .glowing(true)
  .effect('minecraft:strength', 1, -1, 1.0)
  .equipment('mainhand', 'minecraft:netherite_sword', 0.5, 0.02)
  .register()

effect(id, amplifier, duration, chance) — a duration of -1 is permanent. equipment(slot, item, chance, dropChance) — slots: mainhand, offhand, head, chest, legs, feet.

`UMA.mobRule(id)`

UMA.mobRule('nadien_teaks:zombies')
  .priority(50)
  .entities('minecraft:zombie', 'minecraft:husk')
  .categories('monster')
  .boss(false)
  .dimensions('ultimatemodadditions:coliseum')
  .difficulty('nadien_teaks:brutal')
  .replaceVanillaDrops(true)
  .experienceMultiplier(2)
  .drop('minecraft:netherite_scrap', 1, 2, 0.25)
  .coin('1000', 1, 1, 0.2)
  .bag('ultimatemodadditions:common', 0.1)
  .register()

drop(item, min, max, chance) · coin(denomination, min, max, chance) · bag(bagId, chance).

`UMA.lootBag(id)`

UMA.lootBag('nadien_teaks:mythic')
  .name('Mythic Bag')
  .tier('mythic')
  .color(0xFF5C5C)
  .rolls(5, 7)
  .uniqueRolls(true)
  .announce(true)
  .openSound('ultimatemodadditions:loot_bag_open')
  .sortOrder(40)
  .guaranteed('ultimatemodadditions:coin_10000', 1)
  .entry('minecraft:netherite_block', 1, 2, 10)
  .bagEntry('ultimatemodadditions:enchantment', 5)
  .lootTableEntry('minecraft:chests/end_city_treasure', 0.5, 3)
  .register()

entry(item, weight) or entry(item, min, max, weight). guaranteed(item), guaranteed(item, amount) or guaranteed(item, min, max).

`UMA.bagDrop(id)`

Adds loot to bags that already exist, without rewriting them.

UMA.bagDrop('nadien_teaks:copper_everywhere')
  .allTiers()
  .entry('minecraft:copper_ingot', 2, 8, 10)
  .register()

UMA.bagDrop('nadien_teaks:legendary_extra')
  .bag('ultimatemodadditions:legendary')
  .guaranteed('ultimatemodadditions:coin_20000', 1)
  .register()

UMA.bagDrop('nadien_teaks:high_tiers_only')
  .tiers('epic', 'mythic', 'legendary', 'omega')
  .entry('minecraft:nether_star', 1, 1, 4)
  .register()

bag(id), bags(...) and tiers(...) add up. allTiers() is shorthand for tiers('all'). replace(true) wipes the previous contents before adding.

`UMA.trade(id)`

UMA.trade('nadien_teaks:mythic')
  .name('Mythic Bag')
  .category('bags')
  .price(50000)
  .cost('minecraft:emerald', 8)
  .resultBag('nadien_teaks:mythic')
  .sortOrder(90)
  .register()

result(item) / result(item, amount) for items, resultBag(id) for bags. price is money and is paid with any combination of coins, with change.

Escape hatches

When a builder does not cover something, the raw* methods take an object as-is:

UMA.mobRule('nadien_teaks:odd')
  .rawMatch({ regex: ['^minecraft:.*_zombie$'], exclude: ['minecraft:drowned'] })
  .register()

UMA.lootBag('nadien_teaks:books')
  .rawEntry({
    item: 'minecraft:enchanted_book',
    weight: 10,
    components: { 'minecraft:stored_enchantments': { levels: { 'minecraft:mending': 1 } } }
  })
  .register()

The older methods UMA.addLootBag(id, obj), UMA.addTrade(id, obj) and friends are still there and take the whole JSON. They are handy for porting datapacks as-is, but for writing from scratch the builders are better.

Ready-made examples

run/kubejs/ has a uma_ejemplos.js in every folder, commented and tested:

server_scripts/uma_ejemplos.js — everything UMA: bags, additions, trades, a difficulty, a mob rule and a trade with a price. It uses minecraft:bedrock and minecraft:iron_golem_spawn_egg as reference items.
startup_scripts/uma_ejemplos.js — explains why UMA does not belong there and shows what does: registering new items with StartupEvents.registry, to hand them out through UMA bags later.
client_scripts/uma_ejemplos.js — tooltips telling you what each item demands.

Without writing scripts

KubeJS also loads kubejs/data/, so you can drop the JSON in kubejs/data/nadien_teaks/uma/mob_rules/… and it works the same.

When something is wrong

Format errors show up in the server log with the id of the entry, and that entry is dropped without breaking the rest.

Commands

/ums is an alias of /uma: everything works under both names.

/uma tps
/uma ping [players]
/uma coliseum enter | leave
/uma rebuild_arena
/uma spawners list | place | clear
/uma difficulty get | list | set <id>
/uma bag <players> <bag> [amount]

`tps`

Shows the server's real performance, which most mods report badly:

Average TPS and MSPT over the last 100 ticks, against the 50 ms budget.
The worst tick in that window.
MSPT for each dimension separately.

The colours mark when it is getting tight (yellow) or bad (red).

`ping`

With no arguments it shows yours. With a selector, everyone's. Green below 100 ms, yellow up to 250, red above.

`coliseum`

enter takes you to the arena and remembers where you came from; leave puts you back there.

`spawners`

list counts the spawners in the coliseum, place puts them back according to the config wiping the existing ones, and clear removes them all. place and clear need permission level 2. See Coliseum.

`rebuild_arena`

Rebuilds the amphitheatre. Useful if you changed the radius or the height in the config, or if someone wrecked it. Needs permission level 2.

`difficulty`

get shows the active difficulty, list shows the available ones, set changes it for the whole save. It is the one used by mob rules that do not declare their own. set needs permission level 2.

Hands out bags by id. Needs permission level 2.

Configuration

config/ultimatemodadditions-common.toml

These are the broad switches. The content itself lives in JSON, not here.

`[coliseum]`

Option	Default	What it does
`enabled`	true	Turns the dimension on
`build_arena`	true	Builds the amphitheatre the first time
`arena_radius`	30	Radius of the sand floor
`arena_floor_y`	64	Height of the floor
`player_count_scaling`	0.25	Extra scaling per player

Also the default difficulty and whether custom loot only applies inside the coliseum.

`[coliseum.portal]`

Option	Default	What it does
`enforce_requirements`	true	When `false` the portal lets anyone through
`required_experience_levels`	100	Experience levels; they are not spent

See Coliseum.

`[coliseum.spawners]`

Option	Default	What it does
`enabled`	true	Places spawners when the arena is built
`entities`	12 hostile mobs	Which types to use, one per spawner
`count`	12	How many to place; 0 places none
`min_spawn_delay`	200	Shortest wait between batches, in ticks
`max_spawn_delay`	600	Longest wait between batches, in ticks
`spawn_count`	4	How many mobs each batch tries to place
`max_nearby_entities`	8	Stops once this many are already alive nearby
`required_player_range`	24	How close a player has to be
`spawn_range`	6	How far from the spawner mobs can appear

See Coliseum.

`[mob_scaling]`

Turns scaling on, whether it only applies inside the coliseum, global multipliers and a health cap.

`[coins]` and `[loot_bags]`

Turn each system on, whether they only work inside the coliseum, base chance and amounts, and whether only player kills count.

Full example

A small pack that touches everything: a difficulty, a mob rule, a bag, an addition to the bags that already exist and an offer. All under the nadien_teaks namespace.

It goes in config/openloader/data/nadien_teaks/ with OpenLoader, or in world/datapacks/nadien_teaks/data/nadien_teaks/ if you prefer a plain datapack.

`uma/difficulty/brutal.json`

{
  "name": "Brutal",
  "health_multiplier": 6.0,
  "damage_multiplier": 3.0,
  "speed_multiplier": 1.15,
  "armor_bonus": 8.0,
  "armor_toughness_bonus": 3.0,
  "knockback_resistance": 0.3,
  "follow_range_bonus": 16.0,
  "experience_multiplier": 3.0,
  "coin_multiplier": 4.0,
  "bag_chance_bonus": 0.08,
  "extra_loot_rolls": 1,
  "glowing": true,
  "effects": [
    { "effect": "minecraft:strength", "amplifier": 1, "duration": -1, "chance": 1.0 }
  ],
  "equipment": {
    "mainhand": { "item": "minecraft:netherite_sword", "chance": 0.4, "drop_chance": 0.02 },
    "head": { "item": "minecraft:netherite_helmet", "chance": 0.3 }
  }
}

`uma/mob_rules/wither_skeletons.json`

{
  "priority": 50,
  "match": { "entities": ["minecraft:wither_skeleton"] },
  "dimensions": ["ultimatemodadditions:coliseum"],
  "difficulty": "nadien_teaks:brutal",
  "replace_vanilla_drops": false,
  "experience_multiplier": 2.0,
  "drops": [
    { "item": "minecraft:netherite_scrap", "count": { "min": 1, "max": 2 }, "chance": 0.25,
      "looting_bonus": 0.05 }
  ],
  "coins": [
    { "tier": "1000", "count": 1, "chance": 0.35 }
  ],
  "bags": [
    { "bag": "nadien_teaks:boss_reward", "chance": 0.05 }
  ]
}

`uma/loot_bags/boss_reward.json`

{
  "name": "Boss Reward",
  "tier": "legendary",
  "color": 16733525,
  "sort_order": 45,
  "rolls": { "min": 3, "max": 5 },
  "unique_rolls": true,
  "announce": true,
  "open_sound": "ultimatemodadditions:loot_bag_open",
  "guaranteed": [
    { "item": "ultimatemodadditions:coin_20000", "count": { "min": 1, "max": 2 } }
  ],
  "entries": [
    { "item": "minecraft:netherite_ingot", "count": { "min": 1, "max": 2 }, "weight": 10 },
    { "item": "minecraft:elytra", "count": 1, "weight": 2 },
    { "bag": "ultimatemodadditions:enchantment", "count": 1, "weight": 6 },
    { "loot_table": "minecraft:chests/end_city_treasure", "weight": 4 }
  ]
}

`uma/loot_bag_additions/copper_everywhere.json`

{
  "tiers": ["all"],
  "entries": [
    { "item": "minecraft:copper_ingot", "count": { "min": 2, "max": 8 }, "weight": 10 }
  ],
  "replace": false
}

`uma/trades/boss_reward.json`

{
  "name": "Boss Reward",
  "category": "bags",
  "sort_order": 90,
  "price": 50000,
  "cost": [ { "item": "minecraft:emerald", "count": 8 } ],
  "result": { "bag": "nadien_teaks:boss_reward", "count": 1 },
  "enabled": true
}

The same thing in KubeJS

All of the above in a single file, kubejs/server_scripts/nadien_teaks.js:

UMA.difficulty('nadien_teaks:brutal')
  .name('Brutal')
  .health(6).damage(3).speed(1.15)
  .armor(8).armorToughness(3).knockbackResistance(0.3).followRange(16)
  .experience(3).coins(4).bagChance(0.08).extraRolls(1)
  .glowing(true)
  .effect('minecraft:strength', 1, -1, 1.0)
  .equipment('mainhand', 'minecraft:netherite_sword', 0.4, 0.02)
  .register()

UMA.lootBag('nadien_teaks:boss_reward')
  .name('Boss Reward')
  .tier('legendary')
  .color(0xFF5555)
  .rolls(3, 5)
  .uniqueRolls(true)
  .announce(true)
  .guaranteed('ultimatemodadditions:coin_20000', 1, 2)
  .entry('minecraft:netherite_ingot', 1, 2, 10)
  .entry('minecraft:elytra', 2)
  .bagEntry('ultimatemodadditions:enchantment', 6)
  .lootTableEntry('minecraft:chests/end_city_treasure', 1.0, 4)
  .register()

UMA.mobRule('nadien_teaks:wither_skeletons')
  .priority(50)
  .entities('minecraft:wither_skeleton')
  .dimensions('ultimatemodadditions:coliseum')
  .difficulty('nadien_teaks:brutal')
  .experienceMultiplier(2)
  .drop('minecraft:netherite_scrap', 1, 2, 0.25)
  .coin('1000', 1, 1, 0.35)
  .bag('nadien_teaks:boss_reward', 0.05)
  .register()

UMA.bagDrop('nadien_teaks:copper_everywhere')
  .allTiers()
  .entry('minecraft:copper_ingot', 2, 8, 10)
  .register()

UMA.trade('nadien_teaks:boss_reward')
  .name('Boss Reward')
  .category('bags')
  .price(50000)
  .cost('minecraft:emerald', 8)
  .resultBag('nadien_teaks:boss_reward')
  .sortOrder(90)
  .register()

/reload and you are done. Format errors show up in the server log with the id of the entry, and that entry is dropped without breaking the rest.

The skill system

It used to live here and now has a mod of its own: Ultimate Skills, a node tree where every node, connection, bonus and effect is defined in JSON or KubeJS. The two mods are independent — install either one on its own, or both.

Ultimate Mod Additions 1.21.1 Wiki EN

Ultimate Mod Additions Wiki (English)

Index

What the mod adds

Datapacks

Where the files go

Folders

Shared types

Integer range

match — item and block filter

entity — entity filter

components

Difficulties

Fields

effects

equipment

How the difficulty is chosen

Mob rules

Fields

drops

coins

bags

Loot bags

uma/loot_bags/<id>.json

Tiers

uma/loot_bag_additions/<id>.json

Opening them

Trades

price and cost

result

What cannot be bought

The trading screen

Currency

How they work

In datapacks

Coliseum

What is in it

The portal

Requirements to pass through

Arena spawners

Spawner config

The key

Difficulty

Rebuilding it

Coliseum config

KubeJS

The eight builders

UMA.difficulty(id)

UMA.mobRule(id)

UMA.lootBag(id)

UMA.bagDrop(id)

UMA.trade(id)

Escape hatches

Ready-made examples

Without writing scripts

When something is wrong

Commands

tps

ping

coliseum

spawners

rebuild_arena

difficulty

Configuration

[coliseum]

[coliseum.portal]

[coliseum.spawners]

[mob_scaling]

[coins] and [loot_bags]

Full example

uma/difficulty/brutal.json

uma/mob_rules/wither_skeletons.json

uma/loot_bags/boss_reward.json

uma/loot_bag_additions/copper_everywhere.json

uma/trades/boss_reward.json

The same thing in KubeJS

The skill system

Uh oh!

Uh oh!

Clone this wiki locally

`match` — item and block filter

`entity` — entity filter

`components`

`effects`

`equipment`

`drops`

`coins`

`bags`

`uma/loot_bags/<id>.json`

`uma/loot_bag_additions/<id>.json`

`price` and `cost`

`result`

`UMA.difficulty(id)`

`UMA.mobRule(id)`

`UMA.lootBag(id)`

`UMA.bagDrop(id)`

`UMA.trade(id)`

`tps`

`ping`

`coliseum`

`spawners`

`rebuild_arena`

`difficulty`

`[coliseum]`

`[coliseum.portal]`

`[coliseum.spawners]`

`[mob_scaling]`

`[coins]` and `[loot_bags]`

`uma/difficulty/brutal.json`

`uma/mob_rules/wither_skeletons.json`

`uma/loot_bags/boss_reward.json`

`uma/loot_bag_additions/copper_everywhere.json`

`uma/trades/boss_reward.json`