What does the Skeleton AI skill do?

Edit skeleton bone transforms/hierarchy, retargeting modes, curve metadata, blend profiles, bone constraints, and learn constraints from animations (VibeUE SkeletonService). Socket CRUD, bone enumeration, physics-asset, and material/LOD inspection are owned by the engine SkeletalMeshTools. Use when the user asks to add/transform bones, set retargeting, manage blend profiles or curves, or set bone constraints. For animation bone edits, also load animation-editing.

Why use Skeleton on TypingMind?

Because you install it once and use it with any model. Skeleton is plain Markdown rather than provider-specific code, so the same skill runs on GPT-5, Claude, Gemini, Grok, or a local model — and you can switch model mid-chat without it breaking. TypingMind runs on your own API keys, so you pay providers directly instead of a per-seat subscription, and your skills and chats stay in your own storage.

How do I install Skeleton in TypingMind?

Open Plugins → Skills → Install from GitHub in TypingMind and paste https://github.com/kevinpbuckley/VibeUE/tree/master/Content/Skills/skeleton. TypingMind reads its SKILL.md and bundles its files and installs it as a skill you can enable per chat.

Which AI models can use Skeleton?

Any model you connect in TypingMind. AI skills are plain Markdown instructions rather than provider-specific code, so GPT, Claude, Gemini, Grok, and local models can all load this skill when a request matches it.

How many AI models can I use with Skeleton?

As many as you like. As long as a model supports skills, you can use Skeleton with it — GPT, Claude, Gemini, Grok, DeepSeek, Mistral, Llama and more — all on TypingMind with your own API keys.

Is the Skeleton AI skill free?

Yes. It is published on GitHub by kevinpbuckley under the MIT license. You only pay your own AI provider for the tokens you use.

An AI skill is a reusable instruction bundle that teaches an AI model how to do one specific task. It follows the open Agent Skills format: a SKILL.md file with a name and description, plus any scripts, templates or reference files the model may need. The model reads the instructions only when your request matches the skill, so an installed skill costs nothing until it is used.

How are AI skills different from plugins or MCP servers?

A plugin or MCP server gives a model new tools to call — code that runs somewhere and returns a result. An AI skill gives the model knowledge and process instead: how to approach a task, which steps to follow, what good output looks like. Skills are plain Markdown, so they need no server, no API key and no runtime, and they work with any model.

Skeleton by kevinpbuckley — AI Skill for Any LLM

🧠 Brains complement: IF an unreal-engine-skills-manager tool (external MCP) exists in this session, call it with {action: "load", skill: "animation-system"} for UE domain knowledge on this topic — correct APIs, architecture, best practices — and treat it as the rubric for any review / "best practices" question. If no such tool is available (e.g. running under Claude Code or Codex without that MCP), skip this line entirely and proceed with this skill alone — do NOT attempt the call.

Skeleton & Skeletal Mesh Skill

Architecture (read first): VibeUE extends Unreal's native MCP endpoint. Socket CRUD, bone enumeration, physics-asset assignment, and material/LOD/morph inspection are owned by the engine toolset editor_toolset.toolsets.skeletal_mesh.SkeletalMeshTools (called via call_tool). VibeUE's SkeletonService was trimmed to what the engine doesn't cover: bone transform/hierarchy editing, retargeting config, curve metadata, blend profiles, bone constraints, and learn-from-animations.

Loading skills: skills load through the engine's AgentSkillToolset (ListSkills/GetSkills) — there is no vibeue-skills-manager tool. Run VibeUE services with execute_python_code (unreal.SkeletonService.<method>()); reach engine tools with call_tool (discover with list_toolsets / describe_toolset).

Related Skills:

animsequence / animation-editing - For editing animations with constraint validation (uses skeleton profiles) and keyframes

animation-blueprint - For AnimBP state machines and navigation

Use this skill when: Editing bone transforms/hierarchy, retargeting modes, blend profiles, curve metadata, or bone constraints. For sockets / bone listing / physics asset / materials / LODs, use engine SkeletalMeshTools (see below).

Sockets, bone enumeration, inspection → engine SkeletalMeshTools

These moved to the engine. Discover the exact schemas with describe_toolset("editor_toolset.toolsets.skeletal_mesh.SkeletalMeshTools") and call via call_tool (the mesh argument is a {"refPath": "<SkeletalMesh asset path>"} object):

Task	Engine tool (`SkeletalMeshTools.*`)
List sockets	`get_socket_names`
Add / remove / rename socket	`add_socket`, `remove_socket`, `rename_socket`
Get / set socket transform, get socket bone	`get_socket_transform`, `set_socket_transform`, `get_socket_bone`
List bones / parent / children	`get_bone_names`, `get_bone_parent`, `get_bone_children`
Material slots / get / set	`get_material_slots`, `get_material`, `set_material`
Physics asset get / assign	`get_physics_asset`, `assign_physics_asset`
LODs / vertices / sections / bounds	`get_lod_count`, `get_vertex_count`, `get_section_count`, `get_bounds`
Morph target names	`get_morph_target_names`

python
# Example: add a socket on the hand_r bone, then list sockets
call_tool(toolset_name="editor_toolset.toolsets.skeletal_mesh.SkeletalMeshTools",
          tool_name="add_socket",
          arguments={"mesh": {"refPath": "/Game/Characters/SKM_Mannequin"},
                     "socket_name": "Weapon_R", "bone_name": "hand_r"})
call_tool(toolset_name="editor_toolset.toolsets.skeletal_mesh.SkeletalMeshTools",
          tool_name="set_socket_transform",
          arguments={"mesh": {"refPath": "/Game/Characters/SKM_Mannequin"},
                     "socket_name": "Weapon_R",
                     "transform": {"location": {"x":10,"y":0,"z":0},
                                   "rotation": {"pitch":0,"yaw":90,"roll":0},
                                   "scale": {"x":1,"y":1,"z":1}}})

Note: the engine add_socket always adds the socket to the skeletal mesh. VibeUE's old bAddToSkeleton (skeleton-wide socket) flag is gone — to share a socket across all meshes on a skeleton, add it on each mesh, or add it on the skeleton via unreal.* directly.

Critical Rules

⚠️ Bone Modification Requires Commit

Bone modifications (add, remove, rename, reparent) use a transaction system. Changes are NOT applied until you call commit_bone_changes():

python
import unreal

# Make bone changes
unreal.SkeletonService.add_bone("/Game/SKM_Character", "twist_arm_l", "upperarm_l", unreal.Transform())
unreal.SkeletonService.add_bone("/Game/SKM_Character", "twist_arm_r", "upperarm_r", unreal.Transform())

# ⚠️ CRITICAL: Commit changes!
unreal.SkeletonService.commit_bone_changes("/Game/SKM_Character")

Forgetting to commit = changes are lost!

⚠️ Do NOT reparent bones via SkeletonModifier (known-broken, UE 5.7). Changing a bone's parent and calling commit_bone_changes() fails with a hierarchy-mismatch validation error and can leave the commit stalled (the call may not return cleanly). Add/remove/rename/transform are safe; reparenting is not. If a user needs a different hierarchy, add a new bone at the desired parent and remove the old one rather than reparenting in place.

Sockets are now an engine operation

Socket CRUD is on SkeletalMeshTools (see the table at the top). The engine add_socket attaches to the skeletal mesh; set its offset with set_socket_transform. There is no bAddToSkeleton flag.

Skeleton vs SkeletalMesh Paths

Skeleton operations (retargeting, curves, blend profiles, constraints) use SK_ assets → VibeUE SkeletonService
SkeletalMesh bone transform/hierarchy edits use SKM_ assets → VibeUE SkeletonService
SkeletalMesh sockets / bone listing / inspection use SKM_ assets → engine SkeletalMeshTools

python
# Skeleton operations (VibeUE) - use SK_ path
unreal.SkeletonService.get_skeleton_info("/Game/Characters/SK_Mannequin")
unreal.SkeletonService.set_bone_retargeting_mode("/Game/Characters/SK_Mannequin", "pelvis", "Skeleton")

# Sockets / bone listing (engine) - use SKM_ path via call_tool, e.g.:
# call_tool("editor_toolset.toolsets.skeletal_mesh.SkeletalMeshTools", "get_socket_names",
#           {"mesh": {"refPath": "/Game/Characters/SKM_Mannequin"}})

Retargeting Mode Reference

Mode	Description	Use For
`Animation`	Use animation data directly	Most bones (default)
`Skeleton`	Use skeleton's reference pose	Root, pelvis, IK targets
`AnimationScaled`	Scale animation by skeleton size	Height-scaled characters
`OrientAndScale`	Match orientation and scale	Helper/utility bones

Skeleton Profiles & Constraints

For animation editing with constraint validation, use the skeleton profile methods:

python
import unreal

# Create/refresh skeleton profile with hierarchy and constraints
profile = unreal.SkeletonService.create_skeleton_profile("/Game/SK_Mannequin")
print(f"Skeleton has {profile.bone_count} bones")

# Learn constraints from existing animations
constraints = unreal.SkeletonService.learn_from_animations("/Game/SK_Mannequin", 50, 10)
print(f"Learned from {constraints.animation_count} animations")

# Set manual bone constraints (e.g., elbow as hinge)
unreal.SkeletonService.set_bone_constraints(
    "/Game/SK_Mannequin",
    "lowerarm_r",
    unreal.Rotator(0, 0, 0),     # Min rotation
    unreal.Rotator(0, 145, 0),   # Max rotation
    True,  # Is hinge joint
    1      # Pitch axis (Y)
)

# Validate a rotation against constraints
result = unreal.SkeletonService.validate_bone_rotation(
    "/Game/SK_Mannequin",
    "upperarm_r",
    unreal.Rotator(0, 180, 0),  # Test rotation
    True  # Use learned constraints
)
if not result.is_valid:
    print(f"Clamped to: {result.clamped_rotation}")

See the animsequence skill for complete preview→validate→bake workflow.

Workflows

List All Bones (engine SkeletalMeshTools)

Bone enumeration moved to the engine. Use get_bone_names (hierarchy order, root first) and walk parent/children with get_bone_parent / get_bone_children:

python
# names = call_tool("editor_toolset.toolsets.skeletal_mesh.SkeletalMeshTools",
#                   "get_bone_names", {"mesh": {"refPath": "/Game/Characters/SKM_Mannequin"}})
# for n in names:
#     children = call_tool(... "get_bone_children",
#                          {"mesh": {"refPath": "/Game/Characters/SKM_Mannequin"}, "bone_name": n})

For a richer hierarchy with transforms/depth/retarget mode, VibeUE's create_skeleton_profile(skeleton_path) returns bone_hierarchy (Array[BoneNodeInfo]) — see below.

Add Twist Bones for Better Skinning

python
import unreal

mesh_path = "/Game/Characters/SKM_Character"

# Add forearm twist bones
unreal.SkeletonService.add_bone(
    mesh_path,
    "lowerarm_twist_01_l",
    "lowerarm_l",
    unreal.Transform(location=[12.0, 0.0, 0.0])
)

unreal.SkeletonService.add_bone(
    mesh_path,
    "lowerarm_twist_01_r",
    "lowerarm_r",
    unreal.Transform(location=[12.0, 0.0, 0.0])
)

# Add upperarm twist bones
unreal.SkeletonService.add_bone(
    mesh_path,
    "upperarm_twist_01_l",
    "upperarm_l",
    unreal.Transform(location=[15.0, 0.0, 0.0])
)

unreal.SkeletonService.add_bone(
    mesh_path,
    "upperarm_twist_01_r",
    "upperarm_r",
    unreal.Transform(location=[15.0, 0.0, 0.0])
)

# CRITICAL: Commit the changes
unreal.SkeletonService.commit_bone_changes(mesh_path)
unreal.SkeletonService.save_asset(mesh_path)

Set Up Weapon Sockets (engine SkeletalMeshTools)

Socket CRUD is on the engine toolset. Add the socket, then set its offset transform:

python
mesh = {"refPath": "/Game/Characters/SKM_Character"}
TS = "editor_toolset.toolsets.skeletal_mesh.SkeletalMeshTools"

call_tool(TS, "add_socket", {"mesh": mesh, "socket_name": "Weapon_R", "bone_name": "hand_r"})
call_tool(TS, "set_socket_transform", {"mesh": mesh, "socket_name": "Weapon_R",
          "transform": {"location": {"x":10,"y":0,"z":0},
                        "rotation": {"pitch":0,"yaw":90,"roll":0},
                        "scale": {"x":1,"y":1,"z":1}}})

call_tool(TS, "add_socket", {"mesh": mesh, "socket_name": "Holster_Back", "bone_name": "spine_03"})
call_tool(TS, "set_socket_transform", {"mesh": mesh, "socket_name": "Holster_Back",
          "transform": {"location": {"x":0,"y":-20,"z":0},
                        "rotation": {"pitch":0,"yaw":0,"roll":90},
                        "scale": {"x":1,"y":1,"z":1}}})

Configure Retargeting for Animation Sharing

python
import unreal

skeleton_path = "/Game/Characters/SK_Character"

# Root and pelvis should use Skeleton mode
for bone in ["root", "pelvis"]:
    unreal.SkeletonService.set_bone_retargeting_mode(skeleton_path, bone, "Skeleton")

# IK bones should use Animation mode
for bone in ["ik_foot_l", "ik_foot_r", "ik_hand_l", "ik_hand_r"]:
    unreal.SkeletonService.set_bone_retargeting_mode(skeleton_path, bone, "Animation")

# Add a compatible skeleton for sharing animations
unreal.SkeletonService.add_compatible_skeleton(
    skeleton_path,
    "/Game/Mannequins/SK_Mannequin"
)

unreal.SkeletonService.save_asset(skeleton_path)

Create Upper Body Blend Profile

python
import unreal

skeleton_path = "/Game/Characters/SK_Character"

# Create the blend profile
unreal.SkeletonService.create_blend_profile(skeleton_path, "UpperBody")

# Set lower body to 0 (no blend)
lower_body_bones = ["pelvis", "thigh_l", "thigh_r", "calf_l", "calf_r", "foot_l", "foot_r"]
for bone in lower_body_bones:
    unreal.SkeletonService.set_blend_profile_bone(skeleton_path, "UpperBody", bone, 0.0)

# Set upper body to 1 (full blend)
upper_body_bones = ["spine_01", "spine_02", "spine_03", "clavicle_l", "clavicle_r"]
for bone in upper_body_bones:
    unreal.SkeletonService.set_blend_profile_bone(skeleton_path, "UpperBody", bone, 1.0)

unreal.SkeletonService.save_asset(skeleton_path)

Set Up Morph Target Curves

python
import unreal

skeleton_path = "/Game/Characters/SK_Character"

# Add facial expression curves
facial_curves = ["BrowsUp", "BrowsDown", "EyesClosed", "Smile", "Frown"]
for curve in facial_curves:
    unreal.SkeletonService.add_curve_metadata(skeleton_path, curve)
    unreal.SkeletonService.set_curve_morph_target(skeleton_path, curve, True)

# Add material parameter curves
material_curves = ["EyeGlow", "SkinWetness", "BlushAmount"]
for curve in material_curves:
    unreal.SkeletonService.add_curve_metadata(skeleton_path, curve)
    unreal.SkeletonService.set_curve_material(skeleton_path, curve, True)

unreal.SkeletonService.save_asset(skeleton_path)

Find Bones by Pattern (filter engine bone list)

There is no find_bones — get the full list from the engine get_bone_names and filter in Python:

python
names = call_tool("editor_toolset.toolsets.skeletal_mesh.SkeletalMeshTools",
                  "get_bone_names", {"mesh": {"refPath": "/Game/Characters/SKM_Mannequin"}})
hand_bones  = [n for n in names if "hand"  in n.lower()]
twist_bones = [n for n in names if "twist" in n.lower()]
ik_bones    = [n for n in names if n.lower().startswith("ik_")]

Get Full Skeleton Info

python
import unreal

skeleton_path = "/Game/Characters/SK_Mannequin"

info = unreal.SkeletonService.get_skeleton_info(skeleton_path)
print(f"Skeleton: {info.skeleton_name}")
print(f"  Bones: {info.bone_count}")
print(f"  Compatible Skeletons: {info.compatible_skeleton_count}")
print(f"  Curve Metadata: {info.curve_meta_data_count}")
print(f"  Blend Profiles: {info.blend_profile_count}")
if info.blend_profile_names:
    print(f"    Profiles: {', '.join(info.blend_profile_names)}")

Data Structures

Python Naming Convention: C++ types like FBoneNodeInfo are exposed as BoneNodeInfo in Python (no F prefix).

BoneNodeInfo

Property	Type	Description
`bone_name`	string	Name of the bone
`bone_index`	int	Index in hierarchy
`parent_bone_name`	string	Parent bone (empty = root)
`parent_bone_index`	int	Parent index (-1 = root)
`child_count`	int	Number of direct children
`depth`	int	Depth in hierarchy (0 = root)
`local_transform`	Transform	Transform relative to parent
`global_transform`	Transform	World-space transform
`retargeting_mode`	string	Translation retarget mode
`children`	array[string]	Names of child bones

SkeletonAssetInfo

Property	Type	Description
`skeleton_path`	string	Asset path
`skeleton_name`	string	Display name
`bone_count`	int	Number of bones
`compatible_skeleton_count`	int	Compatible skeletons
`curve_meta_data_count`	int	Curve metadata entries
`blend_profile_count`	int	Blend profiles
`blend_profile_names`	array[string]	Profile names
`preview_forward_axis`	string	Forward axis setting

SkeletalMeshData

Property	Type	Description
`mesh_path`	string	Asset path
`mesh_name`	string	Display name
`skeleton_path`	string	Associated skeleton
`bone_count`	int	Number of bones
`lod_count`	int	LOD levels
`socket_count`	int	Number of sockets
`morph_target_count`	int	Morph targets
`material_count`	int	Materials
`physics_asset_path`	string	Physics asset
`post_process_anim_bp_path`	string	Post-process AnimBP

Common Mistakes

❌ WRONG: Forgetting to commit bone changes

python
unreal.SkeletonService.add_bone(path, "new_bone", "parent", transform)
# Bone is NOT added yet - changes lost!

✅ RIGHT: Always commit bone changes

python
unreal.SkeletonService.add_bone(path, "new_bone", "parent", transform)
unreal.SkeletonService.commit_bone_changes(path)  # NOW it's applied

❌ WRONG: Calling `unreal.SkeletonService.add_socket(...)`

That method was cut — sockets are now engine SkeletalMeshTools:

python
# WRONG: unreal.SkeletonService.add_socket(...)               # no longer exists
# RIGHT: call_tool("editor_toolset.toolsets.skeletal_mesh.SkeletalMeshTools",
#                  "add_socket", {"mesh": {"refPath": "/Game/SKM_Character"}, ...})

❌ WRONG: Not saving after VibeUE modifications

python
unreal.SkeletonService.set_bone_retargeting_mode(path, "pelvis", "Skeleton")
# Changes in memory only - lost on editor close!

✅ RIGHT: Save after modifications

python
unreal.SkeletonService.set_bone_retargeting_mode(path, "pelvis", "Skeleton")
unreal.SkeletonService.save_asset(path)

Engine SkeletalMeshTools (via call_tool) — sockets, bone enumeration, physics asset, materials, LODs, morph targets.
animation-editing / animsequence — bone-rotation editing on animations using skeleton profiles.

Publisher	kevinpbuckley
Repository	`VibeUE`
Skill name	`skeleton`
Stars	735
Forks	161
Bundled files	1
License	MIT
Links	Skill source Repository Homepage

Skeleton

Overview

Installation

Install in TypingMind

Install in another agent

Use it in TypingMind

Works with any AI model

Skill instructions

Skeleton & Skeletal Mesh Skill

Sockets, bone enumeration, inspection → engine SkeletalMeshTools

Critical Rules

⚠️ Bone Modification Requires Commit

Sockets are now an engine operation

Skeleton vs SkeletalMesh Paths

Retargeting Mode Reference

Skeleton Profiles & Constraints

Workflows

List All Bones (engine SkeletalMeshTools)

Add Twist Bones for Better Skinning

Set Up Weapon Sockets (engine SkeletalMeshTools)

Configure Retargeting for Animation Sharing

Create Upper Body Blend Profile

Set Up Morph Target Curves

Find Bones by Pattern (filter engine bone list)

Get Full Skeleton Info

Data Structures

BoneNodeInfo

SkeletonAssetInfo

SkeletalMeshData

Common Mistakes

❌ WRONG: Forgetting to commit bone changes

✅ RIGHT: Always commit bone changes

❌ WRONG: Calling `unreal.SkeletonService.add_socket(...)`

❌ WRONG: Not saving after VibeUE modifications

✅ RIGHT: Save after modifications

Related

Bundled files

Frequently asked questions

Set up your own AI workspace now

Overview

Installation

Install in TypingMind

Install in another agent

Use it in TypingMind

Works with any AI model

Skill instructions

Skeleton & Skeletal Mesh Skill

Sockets, bone enumeration, inspection → engine SkeletalMeshTools

Critical Rules

⚠️ Bone Modification Requires Commit

Sockets are now an engine operation

Skeleton vs SkeletalMesh Paths

Retargeting Mode Reference

Skeleton Profiles & Constraints

Workflows

List All Bones (engine SkeletalMeshTools)

Add Twist Bones for Better Skinning

Set Up Weapon Sockets (engine SkeletalMeshTools)

Configure Retargeting for Animation Sharing

Create Upper Body Blend Profile

Set Up Morph Target Curves

Find Bones by Pattern (filter engine bone list)

Get Full Skeleton Info

Data Structures

BoneNodeInfo

SkeletonAssetInfo

SkeletalMeshData

Common Mistakes

❌ WRONG: Forgetting to commit bone changes

✅ RIGHT: Always commit bone changes

❌ WRONG: Calling unreal.SkeletonService.add_socket(...)

❌ WRONG: Not saving after VibeUE modifications

✅ RIGHT: Save after modifications

Related

Bundled files

Frequently asked questions

Related AI Skills

Set up your own AI workspace now

❌ WRONG: Calling `unreal.SkeletonService.add_socket(...)`