Cordyceps MCP
A Rhino 8 plugin lets agents build parametric models in Grasshopper and run renders from a plain-language description.
- 111 ★ on the repository
- Last commit
- MIT
Extended access
Why this level
- The agent edits the Grasshopper document and Rhino scene while undo is disabled.
- The plugin opens a local HTTP port reachable by processes on this machine.
Install
- Works in
Manual install
Rhino 8: команда PackageManager, поиск Cordyceps, Install, затем перезапуск RhinoThe recommended path from the README. Manually: download `Cordyceps.gha` from releases, unblock it and place it in the Grasshopper components folder.
Access and checks
How we reviewExtended accessThe tool runs code or makes network calls and only reads external data.
- The agent edits the Grasshopper document and Rhino scene while undo is disabled.
- The plugin opens a local HTTP port reachable by processes on this machine.
This is third-party code. Review the repository files before installing.
What it does
Cordyceps embeds an MCP server in Grasshopper. An agent adds components to the canvas, wires them together, sets values and groups blocks. On the Rhino side it bakes geometry, manages layers, assigns PBR materials and starts a render. There are seven tools with over a hundred actions: related operations share one tool with an `action` parameter to keep context small. The same calls work from Python or any MCP client without a model. Guides on data trees and type systems are served as resources.
Who it is for. Architects and designers who build parametric models in Rhino and want an agent to handle routine canvas work in Grasshopper.
Good fit when
- You need a draft Grasshopper definition from a verbal description.
- A Rhino scene must be baked, layered and rendered without manual clicks.
- You want to inspect a Grasshopper canvas and find where the data flow breaks.
- A parametric scene is assembled by a Python script over an MCP client, no model involved.
Not a fit when
- Rhino is older than 8.21 or .NET 8 is not available.
- The work happens outside Rhino and Grasshopper, for example in another CAD package.
- Canvas edits must be rolled back with undo, which the plugin disables.
Example request
Build a composition of five geometric solids in Grasshopper, bake it to Rhino, assign materials and produce a final render.MCP
- Transport
- http
- Authentication
- not required
Limitations
Requires Rhino 8.21 or newer and .NET 8. Undo and redo are disabled; document snapshots serve as rollback, with at most 20 kept and the oldest evicted. The server listens on HTTP at local port 26929 and runs while the Cordyceps component sits on the canvas. A manual install requires unblocking the `Cordyceps.gha` file. Last commit in September 2026. The plugin opens a local port without a password, so keep Rhino on a trusted machine and remove the component after work.
How to disable. Remove the Cordyceps component from the canvas and drop the MCP entry in your client. Uninstall the plugin through the Rhino Package Manager or delete `Cordyceps.gha` from the components folder.
FAQ
Which tools are included?
Seven: `gh_canvas`, `gh_wire`, `gh_document`, `gh_script`, `gh_inspect` for Grasshopper and `rhino_scene`, `rhino_render` for Rhino. The `action` parameter selects the operation.
How do I connect Claude Code?
Run `claude mcp add --transport http cordyceps http://127.0.0.1:26929/mcp`, with the Cordyceps component already on the canvas.
How do I connect Claude Desktop?
Through the `mcp-remote` bridge, because the client speaks stdio. Node.js is required and the address is the same, `http://127.0.0.1:26929/mcp`.
What if a component is not found?
Call `gh_canvas` with `action='search'` and a query; the search returns exact component names.
How can I see request traffic?
Set the component input `DebugLevel` to 1 or higher and the exchange appears in Rhino command history.
Discussion
No questions or reviews yet.
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README in short
The server starts with the canvas component and listens on a local HTTP port. Port and debug level are set through component inputs.