RhinoMCPServer

A plugin for executing Model Context Protocol (MCP) server in Rhinoceros. It provides Rhino's functionality as MCP tools and enables efficient communication with MCP clients.

Overview

This plugin exposes Rhino's functionality to MCP clients using the official Model Context Protocol C# SDK. Instead of WebSocket communication, it adopts Server-Sent Events (SSE) to achieve more efficient and lightweight bidirectional communication.

Project Structure

The project consists of the following libraries:

• RhinoMCPServer.Common: Common foundation for MCP tools (interfaces, tool management, etc.)
• RhinoMCPServer.Plugin: Main Rhino plugin implementation
• RhinoMCPTools.Basic: Basic geometry operation tools
• RhinoMCPTools.Misc: Utility tools
• RhinoMCPTools.Grasshopper: Grasshopper integration tools

graph TB
    subgraph MCP Client
      X[Claude Desktop etc...]
    end

    subgraph MCP Server
      subgraph Plugin
          A[RhinoMCPServer.Plugin<br>Main Plugin]
      end

      subgraph Common
          B[RhinoMCPServer.Common<br>MCP Tool Foundation]
      end

      subgraph "MCP Tools (Dynamically Extensible)"
          C[RhinoMCPTools.Basic<br>Basic Geometry Tools]
          D[RhinoMCPTools.Misc<br>Utility Tools]
          E[RhinoMCPTools.Grasshopper<br>Grasshopper Component Operations]
      end
    end

    A --> B
    C --> B
    D --> B
    E --> B
    X -->|"SSE connection"| A

    classDef plugin fill:#949,stroke:#333,stroke-width:2px;
    classDef common fill:#595,stroke:#333,stroke-width:2px;
    classDef tools fill:#559,stroke:#333,stroke-width:2px;

    class A plugin;
    class B common;
    class C,D,E tools;

Loading

Plugin Extensibility

MCP tools are dynamically loaded from DLLs, which means:

• New tools can be added by simply including new DLLs
• Easy addition and removal of plugins
• New tools are automatically recognized upon server restart

Usage Example

Drawing from Sketch & Attribute Information Assignment

movie.mp4

Tracing Existing Drawings

movie2.mp4

Layer Organization

movie3.mp4

Grasshopper Agent

movie4.mp4

System Requirements

• Rhino 9 WIP
• .NET 8.0 Runtime

How to Use

Starting the MCP Server

1. Enter StartMCPServer in Rhino's command line
2. Port number configuration
   • Default: 3001 (automatically used when pressing Enter)
   • Custom: Any port number can be entered
3. After server startup, it waits for MCP client connections on the specified port

Connecting with MCP Clients

Currently, Claude Desktop's MCP client does not directly support SSE connections, so you need to use the MCP server that bridges standard I/O to SSE.

Provided MCP Tools

RhinoMCPTools.Basic

Basic geometry operation and drafting tools.

Drafting Tools (Drafting)

• linear_dimension

  • Function: Creates a linear dimension between two points
  • Parameters:
    • start (object, required) - Start point coordinates
      • x (number, required) - X coordinate
      • y (number, required) - Y coordinate
      • z (number, optional, default: 0) - Z coordinate
    • end (object, required) - End point coordinates
      • x (number, required) - X coordinate
      • y (number, required) - Y coordinate
      • z (number, optional, default: 0) - Z coordinate
    • offset (number, optional, default: 1.0) - Offset distance for dimension line
    • scale (number, optional, default: 1.0) - Dimension scale value (must be greater than 0)

• set_dimension_scale

  • Function: Sets the dimension scale of dimension objects
  • Parameters:
    • guids (array of string, required) - Array of GUIDs of the dimension objects to modify
    • scale (number, required) - The new dimension scale value (must be greater than 0)

Geometry Tools (Geometry)

• sphere

  • Function: Create a sphere in Rhino
  • Parameters:
    • radius (number, required) - Sphere radius (in current Rhino units)
    • x (number, optional, default: 0) - X coordinate of sphere center
    • y (number, optional, default: 0) - Y coordinate of sphere center
    • z (number, optional, default: 0) - Z coordinate of sphere center

• circle

  • Function: Create a circle from center point and radius
  • Parameters:
    • center (object, required) - Center point of the circle
      • x (number, required) - X coordinate
      • y (number, required) - Y coordinate
      • z (number, optional, default: 0) - Z coordinate
    • radius (number, required) - Circle radius (must be greater than 0)

• rectangle

  • Function: Create a rectangle from center point, width (x-direction), and height (y-direction)
  • Parameters:
    • center (object, required) - Center point of the rectangle
      • x (number, required) - X coordinate
      • y (number, required) - Y coordinate
      • z (number, optional, default: 0) - Z coordinate
    • width (number, required) - Width of the rectangle (x-direction, must be greater than 0)
    • height (number, required) - Height of the rectangle (y-direction, must be greater than 0)

• polyline

  • Function: Create a polyline from specified points
  • Parameters:
    • points (array, required) - Array of points defining polyline vertices (minimum 2 points required)
      • Parameters for each point:
        • x (number, required) - X coordinate
        • y (number, required) - Y coordinate
        • z (number, optional, default: 0) - Z coordinate

• move_objects

  • Function: Move specified Rhino objects along a vector
  • Parameters:
    • guids (array of string, required) - Array of GUIDs of the objects to move
    • vector (object, required) - Movement vector
      • x (number, required) - X component of movement distance
      • y (number, required) - Y component of movement distance
      • z (number, optional, default: 0) - Z component of movement distance

• get_geometry_info

  • Function: Get geometric information of a Rhino object
  • Parameters:
    • guid (string, required) - GUID of the target Rhino object
  • Return value: Detailed information based on object type
    • For Polyline:
      • points (array) - Array of vertex coordinates
      • length (number) - Total length of the polyline
      • is_closed (boolean) - Whether the polyline is closed
      • segment_count (number) - Number of segments
      • point_count (number) - Number of vertices
    • For Circle:
      • center (object) - Center point coordinates
      • radius (number) - Radius
      • circumference (number) - Circumference
      • diameter (number) - Diameter
      • plane (object) - Circle's plane information
    • For Surface:
      • is_periodic (boolean) - Whether the surface is periodic
      • is_singular (boolean) - Whether the surface has singularities
      • domain (object) - Parameter domain
      • bounding_box (object) - Bounding box
    • For Brep:
      • face_count (number) - Number of faces
      • edge_count (number) - Number of edges
      • vertex_count (number) - Number of vertices
      • is_solid (boolean) - Whether it's a solid
      • is_manifold (boolean) - Whether it's manifold
      • area (number) - Surface area
      • volume (number) - Volume (only for solids)

Layer Tools (Layer)

• create_layer

  • Function: Create a new layer in Rhino
  • Parameters:
    • full_path (string, required) - Full path of the layer to create (e.g., 'Parent::Child::Grandchild')
    • color (string, optional) - Color of the layer in hex format (e.g., '#FF0000')
    • visible (boolean, optional, default: true) - Whether the layer is visible
    • locked (boolean, optional, default: false) - Whether the layer is locked

• change_object_layer_by_full_path

  • Function: Change an object's layer by specifying the layer's full path
  • Parameters:
    • guid (string, required) - GUID of the target Rhino object
    • layer_full_path (string, required) - Full path of the target layer (e.g., 'Parent::Child::Grandchild')

• change_object_layer_by_index

  • Function: Change an object's layer by specifying the layer index
  • Parameters:
    • guid (string, required) - GUID of the target Rhino object
    • layer_index (number, required) - Index of the target layer

• list_layers

  • Function: Retrieve information about all layers in the document
  • Parameters: None
  • Return value: Array of layer information
    • full_path (string) - Full path of the layer
    • index (number) - Layer index
    • id (string) - Layer ID
    • color (string) - Layer color in hex format
    • visible (boolean) - Layer visibility state
    • locked (boolean) - Layer locked state

Object Tools (Object)

• delete_object

  • Function: Delete a Rhino object with specified GUID
  • Parameters:
    • guid (string, required) - GUID of the object to delete

• delete_objects

  • Function: Deletes multiple Rhino objects by their GUIDs
  • Parameters:
    • guids (array of string, required) - Array of GUIDs of the objects to delete

• set_text_dot_size

  • Function: Sets the font height of text dots
  • Parameters:
    • guids (array of string, required) - Array of GUIDs of the text dots to modify
    • font_height (number, required) - New font height (minimum value: 1)

• set_user_text

  • Function: Set user text attributes for a Rhino object
  • Parameters:
    • guid (string, required) - GUID of the target Rhino object
    • key (string, required) - Key for the user text attribute
    • value (string, required) - Value to set

• set_object_name

  • Function: Set the name of a Rhino object
  • Parameters:
    • guid (string, required) - GUID of the target Rhino object
    • name (string, required) - Name to set for the object

• get_object_name

  • Function: Get the name of a Rhino object
  • Parameters:
    • guid (string, required) - GUID of the target Rhino object
  • Return value:
    • name (string) - Object's name (empty string if not set)

• get_object_attributes

  • Function: Get the attributes of a Rhino object
  • Parameters:
    • guid (string, required) - GUID of the target Rhino object
  • Return value: Object's attribute information
    • name (string) - Object's name
    • layer_index (number) - Layer index
    • layer_name (string) - Layer name
    • object_color (object) - Object's color
      • r (number) - Red component (0-255)
      • g (number) - Green component (0-255)
      • b (number) - Blue component (0-255)
      • a (number) - Alpha value (0-255)
    • color_source (string) - Color source
    • plot_color (object) - Plot color
      • r (number) - Red component (0-255)
      • g (number) - Green component (0-255)
      • b (number) - Blue component (0-255)
      • a (number) - Alpha value (0-255)
    • plot_weight (number) - Plot line weight
    • visible (boolean) - Visibility state
    • mode (string) - Object mode (Normal/Locked/Hidden etc.)
    • object_type (string) - Object type
    • user_text (object) - User text attributes (key-value pairs)

View Tools (View)

• capture_viewport
  • Function: Captures the specified Rhino viewport as an image
  • Parameters:
    • viewportName (string, optional) - The name of the viewport to capture (uses active viewport if not specified)
    • width (number, optional) - The width of the captured image in pixels (uses current viewport width if not specified)
    • height (number, optional) - The height of the captured image in pixels (uses current viewport height if not specified)
    • format (string, optional, enum: ["png", "jpg"], default: "png") - The image format to use
    • show_object_labels (boolean, optional, default: true) - Whether to display simple symbol labels (A, B, C..., AA, AB...) for objects in the viewport
    • font_height (number, optional, default: 20.0) - Font size for the labels

RhinoMCPTools.Misc

Utility tools.

• echo
  • Function: Echo back input text (for health check)
  • Parameters:
    • message (string, required) - Text to echo back

RhinoMCPTools.Grasshopper

Grasshopper integration tools.

Component Management (Components)

• get_canvas_components

  • Function: Retrieve information about all components on the Grasshopper canvas
  • Parameters:
    • include_params (boolean, optional, default: false) - Whether to include parameter information
  • Return value: Array of component information
    • guid (string) - Component's GUID
    • name (string) - Component name
    • nickname (string) - Component's nickname
    • description (string) - Component description
    • category (string) - Category
    • subcategory (string) - Subcategory
    • position (object) - Position on canvas
      • x (number) - X coordinate
      • y (number) - Y coordinate
    • parameters (object, included when include_params is true)
      • input (array) - Array of input parameters
        • name (string) - Parameter name
        • nickname (string) - Parameter nickname
        • description (string) - Parameter description
        • type_name (string) - Parameter type name
      • output (array) - Array of output parameters
        • name (string) - Parameter name
        • nickname (string) - Parameter nickname
        • description (string) - Parameter description
        • type_name (string) - Parameter type name

• get_available_components

  • Function: Get a list of available Grasshopper components
  • Parameters:
    • filter (string, optional) - Filter components by name
    • category (string, optional) - Filter components by category
  • Return value: Array of component information
    • name (string) - Component name
    • description (string) - Component description
    • type_name (string) - Component type name
    • is_param (boolean) - Whether it's a parameter component
    • category (string) - Category
    • sub_category (string) - Subcategory

• create_component

  • Function: Create a specified Grasshopper component on the canvas
  • Parameters:
    • type_name (string, required) - Fully qualified name of the component to create
    • x (number, optional, default: 0) - X coordinate on canvas
    • y (number, optional, default: 0) - Y coordinate on canvas
  • Return value: Created component information
    • guid (string) - Component's GUID
    • name (string) - Component name
    • position (object) - Placement position
      • x (number) - X coordinate
      • y (number) - Y coordinate
    • parameters (object) - Parameter information
      • input (array) - Array of input parameters
      • output (array) - Array of output parameters

• delete_component

  • Function: Delete a component from the canvas
  • Parameters:
    • component_id (string, required) - GUID of the component to delete

Wire Connections (Wires)

• connect_component_wire

  • Function: Connect a wire between two component parameters
  • Parameters:
    • source_param_id (string, required) - GUID of the source parameter
    • target_param_id (string, required) - GUID of the target parameter

• disconnect_component_wire

  • Function: Disconnect a wire between component parameters
  • Parameters:
    • source_param_id (string, required) - GUID of the source parameter
    • target_param_id (string, required) - GUID of the target parameter

Parameter Control (Parameters)

• configure_number_slider

  • Function: Configure settings for a number slider component
  • Parameters:
    • slider_id (string, required) - GUID of the slider component
    • value (number, required) - Value to set
    • minimum (number, optional) - Minimum value setting
    • maximum (number, optional) - Maximum value setting

• set_panel_text

  • Function: Set text for a panel component
  • Parameters:
    • panel_id (string, required) - GUID of the panel component
    • text (string, required) - Text to set

Logs

Server logs are saved in:

• logs/MCPRhinoServer_.log within the plugin directory

License

This project is released under the MIT License. Please refer to the LICENSE file for details.