RhinoMCP

Control Rhino 3D and Grasshopper with AI, in plain language.

RhinoMCP connects Rhino to AI agents through the Model Context Protocol, so assistants like Claude and Cursor can model geometry, read your document, and build Grasshopper definitions for you, just by chatting.

Quick start · What it can do · Usage · Examples · Tool reference

English · 简体中文

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Highlights

• Describe what you want and the assistant builds it in Rhino.
• It reads your document and can capture the viewport, so it works from what is actually on screen.
• It scripts Grasshopper for you: finding components, wiring them, setting sliders, and solving.
• A single plugin and a single config entry cover both Rhino and Grasshopper.
• When you need more control, it can run native Rhino commands, RhinoScript-Python, or RhinoCommon C#.

Note

RhinoMCP targets Rhino 8 on Windows and macOS.

Demos

Two-way interaction: the AI both creates and reads geometry.

Custom scripts: the AI writes and runs scripts inside Rhino.

Prefer a walkthrough? Nate made a showcase and install tutorial on YouTube.

What it can do

Rhino

Area	What the AI can do
Create geometry	Points, lines, polylines, circles, arcs, ellipses, curves, boxes, spheres, cones, cylinders, and surfaces, one at a time or in batches
Transform & edit	Move, rotate, scale, recolor, rename, and delete objects
Advanced modeling	Loft, extrude, sweep, offset, pipe; boolean union, difference, and intersection
Curve operations	Project, intersect, and split curves
Layers & attributes	Create, delete, and switch layers; read and write object attributes
Inspect & select	Document summaries, object info, and filtered selection (by name, color, or category, with AND / OR logic)
See the model	Capture the viewport so the AI gets visual feedback
Analyze	Measure length, area, volume, bounding boxes, and more
Go deeper	Run any Rhino command, execute RhinoScript-Python, or run RhinoCommon C#, with built-in RhinoScript docs lookup

Grasshopper

Area	What the AI can do
Find components	Search the installed component library and inspect a component's inputs and outputs before placing it
Build canvases	Add, position, lay out, update, and delete components
Wire it up	Connect and disconnect parameters between components
Set & read values	Drive sliders, toggles, panels, and value lists; read structured data back out of outputs
Solve	Run the solution and surface runtime warnings and errors
Build in one shot	Construct and wire a whole graph, or mutate an existing one, in a single batched operation

Quick start

Three steps: install the Rhino plugin, connect your AI client, then start the bridge in Rhino.

1. Install the Rhino plugin

In Rhino, open Tools → Package Manager, search for rhinomcp, and click Install. Restart Rhino.

2. Connect your AI client

Option A: ask your AI assistant to install it (recommended)

If you use an agentic assistant (Codex, Claude Code, Cursor, Cline, and the like), paste this prompt:

Please install https://github.com/jingcheng-chen/rhinomcp as a local MCP server named `rhino`.

Option B: Install the mcp server or manually edit the config yourself

Codex, in one command:

codex mcp add rhino --env RHINO_MCP_HOST=127.0.0.1 -- uvx rhinomcp

Claude Code, in one command:

claude mcp add rhino -- uvx rhinomcp

ChatGPT: use Codex for the local setup above. ChatGPT apps/MCP connectors currently connect to remote MCP servers, not local stdio commands like uvx rhinomcp. If you want to build a ChatGPT app around RhinoMCP, use ChatGPT developer mode with a remote or tunneled MCP endpoint.

You can also manually edit the config yourself:

{
  "mcpServers": {
    "rhino": {
      "command": "uvx",
      "args": ["rhinomcp"],
      "env": {
        "RHINO_MCP_HOST": "127.0.0.1"
      }
    }
  }
}

Important

The launcher uvx comes from uv. If you don't have it yet: macOS brew install uv · Windows powershell -c "irm https://astral.sh/uv/install.ps1 | iex"

Run only one RhinoMCP server at a time (Codex, Claude, Cursor, etc. — not several at once).

Auto-restart the server with your AI client (optional)

To clean up a stale rhinomcp process each time your client launches:

macOS / Linux

{
  "mcpServers": {
    "rhino": {
      "command": "sh",
      "args": ["-c", "killall rhinomcp 2>/dev/null; uvx rhinomcp"]
    }
  }
}

Windows

{
  "mcpServers": {
    "rhino": {
      "command": "cmd",
      "args": ["/c", "taskkill /F /IM rhinomcp.exe 2>nul & uvx rhinomcp"]
    }
  }
}

3. Start the Rhino bridge

With Rhino open, type mcpstart in the command line. This starts the TCP bridge the server connects to (mcpstop ends it). Run it once per Rhino session.

Usage

With the bridge running and your client connected, you'll see the RhinoMCP tools. From there, just chat: ask the assistant to model something, inspect your scene, or build a Grasshopper graph.

For Grasshopper, you only need Rhino open with mcpstart running. The assistant can open or create the Grasshopper document itself, then build the definition. For example: "create a point attractor pattern with cylinders that have different heights."

Example prompts

Create 6×6×6 boxes on a 10-unit grid from the origin, sizes ramping from 1 to 5, with a blue-to-red gradient color based on size. Use RhinoScript Python.

Make a Rhinoceros animal out of cubic blocks in cartoon colors. Then change its head to red, and rotate the selected object 90° around the Z axis.

Create a point attractor pattern in Grasshopper: a grid of cylinders whose heights change with their distance from an attractor point, with a slider to move the point.

Tool reference

Rhino tools

Tool	Purpose
create_object / create_objects	Create one or many objects
modify_object / modify_objects	Transform or edit one or many objects
delete_object	Delete an object
boolean_union / boolean_difference / boolean_intersection	Boolean operations
loft / extrude_curve / sweep1 / offset_curve / pipe	Advanced surface and solid modeling
project_curve / intersect_curves / split_curve	Curve operations
analyze_objects	Measure length, area, volume, bounding boxes, and more
select_objects	Select by filters (name, color, category; AND / OR)
get_objects / get_object_info / get_selected_objects_info	Query objects
get_object_attributes / update_object_attributes	Read and write object attributes
create_layer / delete_layer / get_or_set_current_layer	Layer management
get_document_summary	Overview of the current document
capture_viewport	Screenshot the viewport for visual feedback
run_command	Run any native Rhino command
execute_rhinoscript_python_code	Execute RhinoScript-Python
execute_rhinocommon_csharp_code	Execute RhinoCommon C#
search_rhinoscript_functions / get_rhinoscript_docs / list_rhinoscript_modules / get_module_functions	RhinoScript API docs lookup
get_commands	List available commands
undo / redo	Undo and redo

Grasshopper tools

Tool	Purpose
gh_create_document / gh_get_document_info / gh_get_canvas_state	Document and canvas inspection
gh_search_components / gh_batch_search_components	Search the component library
gh_list_component_categories / gh_get_available_components	Browse installed components
gh_get_component_type_info / gh_get_component_info	Inspect a component type or instance
gh_list_components	List components on the canvas
gh_add_component / gh_update_component / gh_delete_component	Add, update, or delete components
gh_layout_components	Auto-lay-out the canvas
gh_clear_canvas	Clear the canvas
gh_connect_components / gh_disconnect_components	Wire or unwire parameters
gh_set_parameter_value / gh_get_parameter_value	Drive inputs, read outputs
gh_run_solution / gh_expire_solution	Solve or expire the solution
gh_build_graph / gh_mutate_graph	Build or mutate a whole graph in one batched call
gh_get_graph / gh_clear_graph	Inspect or clear objects by graph id

How it works

AI client ──MCP (stdio)──► rhinomcp (Python) ──TCP 127.0.0.1:1999──► Rhino plugin ──► Rhino + Grasshopper

1. server/: a Python FastMCP server that exposes each tool and forwards it to Rhino.
2. plugin/: a RhinoCommon C# plugin that runs a TCP listener inside Rhino and executes commands on the main thread. Start and stop it with the mcpstart / mcpstop Rhino commands.
3. contracts/: JSON Schema definitions that keep the wire protocol between the two tiers in sync.

IMPLEMENTATION.md has a deeper tour of the code.

Security

The Python server and the Rhino plugin talk over an unauthenticated TCP loopback link (127.0.0.1:1999). Tools such as run_command, execute_rhinoscript_python_code, and execute_rhinocommon_csharp_code give the model an open execution surface inside Rhino. This is fine for local agent use. Do not expose it beyond the loopback interface without adding authentication.

Operator switches (environment variables)

Variable	Default	Effect
RHINO_MCP_HOST	127.0.0.1	Connect target. Refuses non-loopback hosts unless RHINO_MCP_ALLOW_REMOTE=1.
RHINO_MCP_PORT	1999	TCP port.
RHINO_MCP_ENABLE_RUN_COMMAND	1	Set 0 to disable the run_command tool.
RHINO_MCP_ENABLE_RHINOSCRIPT	1	Set 0 to disable RhinoScript-Python execution.
RHINO_MCP_ENABLE_CSHARP	1	Set 0 to disable RhinoCommon C# execution.
RHINO_MCP_VALIDATE	warn	Pre-flight schema validation: off / warn / strict.
RHINO_MCP_TIMEOUT	15.0	Socket timeout in seconds.
RHINO_MCP_DEBUG	0	Verbose logging.

For developers

Build, test, and publish

Python server (run from server/)

uv venv && uv pip install -e ".[dev]"   # set up
uv run pytest                            # run tests (no Rhino needed; uses a mock server)
uv run ruff check src/rhinomcp           # lint
uv run python ../contracts/test_schemas.py   # validate JSON schemas
uv build && uv publish                   # publish to PyPI

C# plugin

dotnet restore plugin/rhinomcp.sln
dotnet build plugin/rhinomcp.sln --configuration Release

To publish the plugin: build in Release, copy manifest.yml into bin/Release, then run yak build and yak push rhinomcp_xxxx.yak.

Contributing

Contributions are welcome. Feel free to open an issue or submit a pull request.

Disclaimer

This is a third-party integration and is not made by McNeel. Built by Jingcheng Chen.

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