Mob Origins

Mob origins are to mobs what player origins are to players: a JSON-defined bundle of powers attached to a LivingEntity, with weighted spawn rules and per-origin drops.

Authored at data/<ns>/origins/mob_origins/<id>.json; loaded by MobOriginDataManager after the player-origin / layer reload pipeline. NeoOrigins-native concept — no Origins-mod legacy format.

📖 See POWER_TYPES.md for the power list shared with player origins. The neoorigins:mob_behavior power (configurable aggression) is mob-only.

ℹ️ Status: this doc is a Phase-5 outline. Full field tables + examples land alongside Phase 6 and the v2.1.0 release.

File shape 

{
  "name": {"text": "Brutal Zombie"},
  "description": {"text": "A hostile zombie variant"},
  "icon": "minecraft:zombie_head",
  "target": {"entity_type": "minecraft:zombie"},
  "powers": ["neoorigins_custom:brutal_zombie_buffs"],
  "spawn_rules": { },
  "drops": { },
  "hidden": false
}

id is injected from the file path — do not write it in the JSON. (Same convention as player origins.)

Top-level fields

  • target — exactly one of entity_type (single id), entity_tag (tag id), or entity_types (array of ids). [TODO: examples + validation rules]
  • powers — list of resolved power ids; powers that aren’t mob-applicable are silently filtered with a [mob-compat] line in logs/neoorigins-compat.log.
  • spawn_rules — optional. Weighted natural-spawn application (Phase 2). [TODO: weight, time_of_day, spawn_reasons, mutex_group, replace, y_range, light_range, location filter (dim / biome / biome_tag / biomes / structure / structure_tag / allow_water_surface / allow_ocean_floor / min_y / max_y / can_see_sky)]
  • drops — optional. Additive or replace drop table layered onto vanilla loot via a global loot modifier (Phase 5). [TODO: mode (additive|replace) / strategy (independent_chance|weighted_pool) / pool_rolls / entries: [{item, count, chance, rolls, weight}]]
  • hidden — when true, the origin is omitted from in-game creator browsers. The mechanical effect still applies.

The neoorigins:mob_behavior power

Configurable, piglin-style aggression. Three modes: NEUTRAL (no targeting), HOSTILE (always targets), CONDITIONAL (targets only while every hostile_when condition holds for the candidate player).

Config fields: aggression, hostile_when, retaliate, anger_linger_ticks, aggro_range, target_filter, call_for_help. [TODO: full field table + examples; condition DSL reuses the existing entity-condition surface verbatim.]

Spawn-egg minting (Phase 4d)

Both surfaces target the saved origin id — Save the draft first if it’s new.

  • /neoorigins mob egg <origin> [entity_type] [count] — mints a vanilla <type>_spawn_egg ItemStack with the origin marker baked into ENTITY_DATA.
  • “Give Spawn Egg” button in the Mob Origin Creator’s Identity tab — same path, prompts for an entity type when the origin’s target is a tag or list.

Right-clicking the egg on the ground spawns the mob with the origin pre-attached. Right-clicking it on a Spawner reconfigures the spawner’s next-spawn data so its natural firings also carry the origin.

Live Mode (Phase 6 — pending)

[TODO: looked-at apply / spawn here / active template. Section drafted when Phase 6 lands.]

Power compatibility

Not every power type works on mobs (HUD / keybind / food / starting-equipment / edible-item / orb-related types are player-only). Powers a mob origin lists are filtered through PowerType.appliesToMobs(config); ineligible powers are dropped with a log line and the rest are applied via MobOriginService.applyMobOriginPowers.

[TODO: full appliesToMobs() table — which power types fire on mobs and which are filtered out.]