Blockbench MCP Overview

For content changes, load blockbench-use first. The running server's tool list and schemas determine available operations; this source skill can describe tools newer than an installed bundle. Tool status and success text are not a substitute for result inspection.

Discover the Host and Workflow

get_capabilities: include_tools=true
# → blockbench, plugin, project, format, formats, tools, notes
list_modes
# → current_mode, modes[{id, available, selected, ...}]

project may be null. Use exact registered format IDs: Generic Model is normally free. Inspect a prospective format with get_capabilities: format_id="free" without switching projects. Detailed feature flags can be null (unknown); compact listings distinguish true flags and unknown flags. Installed plugin formats are supported through discovery rather than a fixed whitelist in these skills.

When a tool depends on editor state, use list_modes and set_mode: mode_id="<returned ID>", then refresh availability. Animate uses animate, not animation. Changing mode does not change project format.

Inspection and IDs

Prefer find_elements_by_criteria and filter_by_material for targeted questions; use list_outline to understand a hierarchy. Read list_textures and list_materials before referring to existing assets. Names can collide, especially a group and its cube, so retain UUIDs.

place_mesh returns {meshes: [{name, uuid, vertex_keys, face_keys}]}. Component arrays follow input order. Other mesh creators and existing meshes can be inspected with get_mesh_info; its vertices and faces have independent next_offset values. Read to null before mutating. Positions and normals are mesh-local. Reinspect after topology changes or undo/redo. See the modeling skill for executable client-orchestration examples.

get_cube_uv: id="<cube UUID>" reads box/per-face mode, face UVs and effective texture dimensions. set_cube_uv edits those values with format checks. list_textures reports uv_size, bitmap_size, and frame_size; create_texture can set an explicit uv_width/uv_height pair in formats with per-texture UV sizing. Schemas and examples are in the texturing skill.

Resources include projects://{id}, nodes://{id}, textures://{id}, and Hytale-specific resources. Discover resource templates and concrete URIs from the live server instead of inventing IDs. Project exports can also return a live .bbmodel resource link.

A Small Model and Animation

This is tool-call pseudocode for a newly intended Bedrock entity. Confirm the format is registered and the project supports animation first.

create_project: name="robot", format="bedrock"
add_group: name="body", origin=[0, 12, 0]
place_cube: elements=[{name: "torso_geo", from: [-4, 12, -2], to: [4, 24, 2]}], group="body"

create_texture: name="skin", width=64, height=64, fill_color="#808080", layer_name="base"
apply_texture: id="torso_geo", texture="skin", applyTo="all"

idle = create_animation: name="idle", animation_length=2, loop=true, bones={}
manage_keyframes: animation_id=idle.uuid, action="create", bone_name="body",
  channel="rotation", keyframes=[
    {time: 0, values: [0, 0, 0]},
    {time: 1, values: [0, 5, 0]},
    {time: 2, values: [0, 0, 0]}
  ]
animation_timeline: animation_id=idle.uuid, action="set_time", time=1
capture_screenshot

Bind idle.uuid to the returned value; it is not a literal tool argument. Inspect UVs before adding detailed texture art. A rest-pose screenshot alone does not verify motion.

Native Armatures

When the running format supports armature_rig, discover the native armature tools: list_armatures, get_armature, add_armature, list_armature_bones, get_armature_bone, add_armature_bone, and the update/remove operations. ArmatureBones and group-based BoneAnimators are different APIs; the general animation tools resolve groups.

For an existing mesh and armature, inspect get_mesh_info for runtime vertex keys and get_vertex_weights: mesh_id="<UUID>" for current weights. set_vertex_weights_batch takes bone_id, mesh_id, and weights: { "<vertex key>": 0.5 }; weights are 0–1. Inspect all contributing weights and deformation at joints after changes; setting one bone's values does not establish a correctly bound or normalized whole rig. Check exporter support for the native rig before promising a skinned runtime asset.

Java Display Transforms

For formats supporting display_mode:

get_display_transform: slot="gui"
set_display_transform: slot="gui", rotation=[30, 225, 0], scale=[0.75, 0.75, 0.75]
enter_display_mode: slot="gui"
capture_screenshot

Display transforms change exported data. Confirm the requested hand, inventory, ground or frame views with their corresponding slots; do not use a camera adjustment to imply those transforms were authored.

Bedrock Block Material Instances

In bedrock_block, get_face_material_instances reads and set_face_material_instance writes names mapped by the target's minecraft:material_instances component.

get_face_material_instances: cube_id="block_geo"
set_face_material_instance: cube_id="block_geo", faces=["up"], material_name="top"

The tools assign face names; they do not create the behavior-pack block components or resource-pack texture definitions. These material instances are separate from PBR texture groups and GPU instancing. Follow material-instance and texture delivery for multiple materials or cutout panels, and the appearance/performance plan before using textures to replace repeated geometry. Entities use client-entity/render-controller bindings rather than this block component. Inspect the geometry export and accompanying target configuration.

Recovery

save_checkpoint inserts a history marker. It does not save a file, preserve an existing redo branch, or make unrecorded script mutations undoable. Use get_undo_stack to locate the marker and count actual entries before undo: steps=N; a paint tool may create multiple native strokes. Preserve intervening user edits.

Use dedicated undo / redo rather than trigger_action for those operations. Direct risky_eval scripts must manage native undo aspects and failure cleanup for mutations. Prefer available dedicated tools and follow the session's existing authorization.

Export

list_export_formats
# Inspect available, has_compile, extension and belongs_to_current_format
export_model: codec_id="project", result_format="embedded"
export_model: codec_id="project", path="C:/models/robot.bbmodel", max_content_length=0

Use an authorized destination on the Blockbench host. Filesystem permission may be handled by the host. only_current_format=true filters the codec listing; use the full listing to discover other available compatible exports.

export_model invokes a codec's compile operation. It does not automatically run the codec's interactive export flow, write all external images, or export separate animation files. Inspect byte_length, output path, truncation and returned content/resource metadata. A truncated text/base64 preview is not a complete downloadable asset. Embedded results contain a complete file only when it fits the response limit.

Select format, dependencies and destination checks using format and delivery guidance. Reopen a copy or inspect the destination app when available; report verification limits accurately.