Minecraft Processor List

Processor List

Processor lists replace blocks placed from structure templates during world generation per rules. Java Edition only.

Definition Format

Registry PROCESSOR_LIST, data pack path worldgen/processor_list (files in data/<namespace>/worldgen/processor_list/; tags in tags/worldgen/processor_list/). A file is either a root array of processors or an object with a processors list. Each processor:

{ "processor_type": "<namespace id>", ... }

Processor Types

• blackstone_replace — replaces stone-type blocks with blackstone variants and iron bars with chains.
• block_age — ages blocks: mossiness (0–1 clamped).
• block_ignore — blocks (list of block states; states not checked): removes those blocks; their positions keep the pre-existing blocks (not overwritten).
• block_rot — randomly removes blocks: integrity (0–1; removal chance), rottable_blocks (ID/array/tag; absent = all blocks).
• capped — caps the number of processed blocks: delegate (recursive processor), limit (int provider; if the structure has fewer blocks, all are processed, else a random subset).
• gravity — shifts the structure vertically per terrain: heightmap (default WORLD_SURFACE_WG; one of the six standard heightmaps), offset (default 0).
• jigsaw_replacement — replaces jigsaw blocks and removes structure void; auto-applied for worldgen jigsaw structures (no need to declare).
• lava_submerged_block — when a structure block replaces lava, blocks with incomplete collision boxes don't replace the lava.
• nop — does nothing.
• protected_blocks — value (ID/list/tag): these blocks can't be overwritten by the structure.
• rule — custom rules, applied in list order:
  • position_predicate (default always true) — test on the distance from the structure start: predicate_type = always_true, linear_pos (3D Manhattan distance; min_chance/max_chance with linear interpolation between min_dist/max_dist; probabilities clamped 0–1), or axis_aligned_linear_pos (same but on one axis = x/y/z, default y, distances positive).
  • input_predicate (required) — rule test applied to the placed block (see the rule-test skill).
  • location_predicate (required) — rule test applied to the block at the position before generation.
  • output_state (required) — the block to place.
  • block_entity_modifier (optional) — modifies the block entity on placement: passthrough (default, keep fields), clear (remove fields), append_static (data NBT added), append_loot (loot_table added, with a seed based on the block position).

Behavior

Processors run in list order per template block; they're also called block processors / structure post-processors. For template pool jigsaw elements, processors run BEFORE terrain adaptation — the actual placement position may differ from the processed position. Definitions load once at server startup (restart required).