Attribute Base Modifier

The Attribute Base Modifier (or ABM) modification allows changing the base values of any attributes for existing mobs.

Basic Information

This mod operates on the server side and requires installation on:

• Dedicated server
• Local server
• Client in single-player mode
• Not required on pure client

Data-Driven Management

The mod's functionality is implemented through JSON files in data packs. It's recommended to familiarize yourself with the basics of Minecraft data packs if you encounter any difficulties.

Rule Registration

Rules are created as JSON files located at: data/<namespace>/abm_rules/<name>.json. The unique rule identifier will be <namespace>:<name>.

All rules are automatically updated when server data is reloaded—for example, when using the /reload command or reloading the world.

Rule Format

Main configuration parameters:

Inclusion filters:

• type — list of mobs to include (can specify specific ID or tag with # prefix)
• spawn_group — mob spawn group (incompatible with type)

Exclusion filters: similar to inclusion parameters

Modifications: array of attributes to modify with parameters:

• attribute — attribute ID
• modifiers — modification methods:
  • type — operation (set, add, multiply)
  • value — numeric value

Additional settings:

• default_enable — default rule activation status

Configuration Example

{
    "include": {
        "spawn_group": "monster"
    },
    "exclude": {
        "type": "#c:bosses"
    },
    "modifies": [
        {
            "attribute": "minecraft:max_health",
            "modifiers": [
                {
                    "type": "add",
                    "value": 100
                }
            ]
        },
        {
            "attribute": "minecraft:armor",
            "modifiers": [
                {
                    "type": "set",
                    "value": 10
                }
            ]
        }
    ]
}

This example increases maximum health of all monster mobs by 100 units and sets their armor to 10 units.

Debug Command

abmrule <rule_id> [enable|disable] — allows temporarily activating or deactivating specific rules.

Note: when data is reloaded, the rule's status reverts to its default value specified in the JSON file.

Frequently Asked Questions

Why don't changes apply to existing mobs?

This is expected behavior. Mob instances already existing in the world don't automatically update their attributes when rules are changed. For testing working settings, it's recommended to create new mobs. Existing ones will update when re-entering the world or loading chunks.

How to preconfigure rules when creating a world?

When building modpacks, it's convenient to use mods for global data packs—for example, Paxi, which allows automatically loading custom data when creating new worlds.

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