keratin 0.1.4

AI-powered Rhino3D MCP bridge — connect Claude to Rhinoceros 3D

keratin

Connect Claude AI to Rhinoceros 3D.

keratin is a Model Context Protocol bridge for Rhino 7. It lets Claude create geometry, manage layers, run boolean operations, drive Grasshopper, and execute arbitrary RhinoScript — all from a conversation.

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How it works

keratin has two components that communicate over a local TCP socket:

Claude ──MCP──▶ keratin (Python 3.10+)  ──TCP:9876──▶  rhino_script.py (Rhino 7, IronPython 2.7)

Component	Runtime	Role
rhino_script.py	IronPython 2.7 inside Rhino	Listens on localhost:9876, executes commands on Rhino's UI thread
keratin (MCP server)	Python 3.10+ on the host	Exposes tools to Claude via the Model Context Protocol

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Installation

1. Rhino-side script (Rhino Package Manager)

In Rhino: Tools > Package Manager > search keratin > Install > Restart Rhino.

2. MCP server (pip)

pip install keratin

3. Configure your MCP client

Claude Desktop — add to claude_desktop_config.json:

{
  "mcpServers": {
    "rhino": {
      "command": "keratin"
    }
  }
}

Claude Code:

claude mcp add rhino -- keratin

LM Studio / other MCP clients — add to your mcp.json:

{
  "mcpServers": {
    "rhino": {
      "command": "keratin",
      "args": []
    }
  }
}

4. Start the listener in Rhino

Type StartKeratin in the Rhino command line. To stop: StopKeratin.

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Tools

keratin exposes 160+ tools covering the full RhinoScriptSyntax API. Popular functions are registered as individual tools for easy discovery; the rest are accessible through category-level tools.

Dedicated tools

Category	Tools
Scene	get_document_summary get_rhino_scene_info get_rhino_layers capture_rhino_viewport
Objects	get_objects get_object_info create_object modify_object delete_object select_objects add_rhino_object_metadata get_rhino_objects_with_metadata get_rhino_selected_objects get_selected_objects_info
Layers	create_layer delete_layer get_or_set_current_layer
Geometry	boolean_union boolean_difference boolean_intersection loft extrude_curve sweep1 offset_curve pipe
Curves	trim_curve join_curves curve_domain trim_curve_by_fraction
Jewelry	ring_blank head_blank section_profile place_head_on_band edge_selector_presets safe_boolean_union safe_boolean_difference loft_sections
Grasshopper	grasshopper_add_components grasshopper_get_definition_info grasshopper_run_solver grasshopper_clear_canvas grasshopper_list_available_components
Code	execute_rhino_code execute_rhinoscript_python_code
Discovery	list_rhino_commands list_rhinoscript_functions look_up_RhinoScriptSyntax

Individual RhinoScript tools (90+)

High-frequency rs.* functions exposed as standalone tools for zero-friction use:

Area	Examples
Curve creation	rs_AddLine rs_AddCircle rs_AddArc3Pt rs_AddEllipse rs_AddInterpCurve rs_AddNurbsCurve rs_AddRectangle rs_AddSpiral rs_AddPolyline rs_AddBlendCurve rs_AddFilletCurve
Curve query	rs_CurveLength rs_CurveStartPoint rs_CurveEndPoint rs_CurveMidPoint rs_CurveClosestPoint rs_CurveDomain rs_CurveArea rs_CurveTangent rs_IsCurve rs_IsCurveClosed
Curve ops	rs_DivideCurve rs_EvaluateCurve rs_OffsetCurve rs_JoinCurves rs_ExplodeCurves rs_SplitCurve rs_RebuildCurve rs_ReverseCurve rs_CloseCurve
Surface creation	rs_AddSphere rs_AddCylinder rs_AddCone rs_AddBox rs_AddTorus rs_AddPipe rs_AddPlanarSrf rs_AddLoftSrf rs_AddSweep1 rs_AddSweep2 rs_AddRevSrf rs_AddEdgeSrf rs_AddNetworkSrf rs_AddPatch
Surface ops	rs_ExtrudeCurveStraight rs_CapPlanarHoles rs_FilletSurfaces rs_OffsetSurface rs_JoinSurfaces rs_ExplodePolysurfaces rs_DuplicateEdgeCurves rs_DuplicateSurfaceBorder rs_ExtractIsoCurve
Surface query	rs_SurfaceArea rs_SurfaceVolume rs_SurfaceNormal rs_SurfaceDomain rs_EvaluateSurface rs_BrepClosestPoint rs_IsSurface rs_IsPolysurface rs_IsPolysurfaceClosed
Object ops	rs_CopyObject rs_MoveObject rs_RotateObject rs_ScaleObject rs_MirrorObject rs_ObjectLayer rs_ObjectName rs_ObjectColor rs_ObjectType
Selection	rs_AllObjects rs_ObjectsByLayer rs_ObjectsByType rs_ObjectsByName rs_SelectedObjects rs_UnselectAllObjects rs_LastCreatedObjects
Mesh	rs_AddMesh rs_MeshBooleanUnion rs_MeshBooleanDifference rs_JoinMeshes rs_MeshToNurb rs_IsMesh
Transform	rs_XformScale rs_XformTranslation rs_TransformObject
View	rs_ZoomExtents rs_ZoomSelected rs_ViewCamera rs_CurrentView rs_Redraw rs_EnableRedraw
Misc	rs_AddPoint rs_AddTextDot rs_BoundingBox rs_Distance rs_Angle rs_AddLayer rs_SetUserText rs_GetUserText rs_AddGroup rs_PlaneFromNormal rs_WorldXYPlane

Category catch-all tools (26)

Any rs.* function not listed above is still accessible through its category tool. Call these with a function name and arguments:

rhinoscript_application · rhinoscript_block · rhinoscript_curve · rhinoscript_dimension · rhinoscript_document · rhinoscript_geometry · rhinoscript_grips · rhinoscript_group · rhinoscript_hatch · rhinoscript_layer · rhinoscript_light · rhinoscript_line · rhinoscript_linetype · rhinoscript_material · rhinoscript_mesh · rhinoscript_object · rhinoscript_plane · rhinoscript_pointvector · rhinoscript_selection · rhinoscript_surface · rhinoscript_toolbar · rhinoscript_transformation · rhinoscript_userdata · rhinoscript_userinterface · rhinoscript_utility · rhinoscript_view

Together these cover all 994 functions in the Rhino 7 RhinoScriptSyntax API.

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Requirements

• Rhinoceros 3D 7 (IronPython 2.7)
• Python 3.10+ on the host machine
• Claude Desktop or Claude Code as the MCP client

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Web server variant

For HTTP / WebSocket access instead of stdio MCP:

keratin-web --host localhost --port 8000

Endpoint	Description
POST /rhino/command	Execute a Rhino command ({"type": "...", "params": {...}})
GET /rhino/scene	Get current scene info
GET /rhino/strategy	Get the recommended Rhino creation strategy
WS /rhino/ws	WebSocket for streaming command execution

CORS is restricted to localhost origins.

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Diagnostics

# Test the Rhino TCP connection
python tools/ops/diagnose_rhino_connection.py

# View recent errors across all logs
python tools/ops/log_manager.py --since-minutes 60 --level ERROR

Log locations:

Source	Location
Rhino listener	~/AppData/Local/RhinoMCP/logs/ (Windows) or ~/Library/Application Support/RhinoMCP/logs/ (macOS)
Server	./logs/server/
Diagnostics	./logs/diagnostics/

Rhino-side logs auto-rotate at 5 MB.

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Building and publishing

PyPI (MCP server):

python -m build
python -m twine upload dist/*

Yak (Rhino Package Manager):

cd yak-package
"C:\Program Files\Rhino 7\System\yak.exe" build
"C:\Program Files\Rhino 7\System\yak.exe" push keratin-0.1.4-any-any.yak

Requires a McNeel account. Run yak login before your first push.

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Attribution

keratin builds on:

• rhino-mcp by Reer — MIT License
• rhinomcp by Jingcheng Chen — Apache License 2.0

See THIRD_PARTY_NOTICES.md and the preserved license texts under third_party/.

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Disclaimer

Not affiliated with McNeel & Associates. Use at your own risk. Always work on copies of important files.