Grasshopper plugin / free beta

Robohopper

Start your Grasshopper factory

Robohopper is your C# component factory. It quickly trains your AI agent and gives it the tools to test components, iterate code, and work freely on your Grasshopper canvas. CLI only, no MCP.

Download the small Rhino installer and drag it into Rhino 8. It fetches the latest published Robohopper package from Rhino's official package server, then opens setup.

download robohopper installer (.rhp)

starter prompt

Use Robohopper in this project. It was installed through its Rhino installer and setup wizard.
First verify that the Robohopper skill and kit are present in this workspace. If either is
missing, stop and tell me that setup is incomplete - do not substitute files from another workspace.

Do not launch Rhino yourself. Ask me to open Rhino 8 and Grasshopper my usual way, then stop.
Only after I confirm Grasshopper is open:
1. Use kit/rhbridge.py to check 127.0.0.1:5200 and 127.0.0.1:9999, including a real value readback.
2. Use the installed Robohopper skill to build what I ask: write, wire and run components, reading
   output "a" rather than the "out" log.

Rules: act on localhost only. Verify by observable effect, not success flags. If something the
package should provide is missing, report it as a packaging problem - do not fake it.

Email optional, for Robohopper updates and new releases. Privacy.

Beta. Tested with Claude Code (Opus 4.8); it should work just as smoothly with Gemini CLI, Codex, or any other external agent you use. Validated on test setups, not yet on production definitions, and not yet code-signed. Windows only for now - the Mac build is not yet validated. Rhino 8 SR18+ with Grasshopper. The local authoring bridge requires a per-session token. The small site installer downloads the current Yak package; the 0.6.0 package records the matching engine checksums. Found something? Write me: design@simonepeluffo.com.

01 / the workflow

Design, set, loop, deliver

DesignThe agent studies your request and maps the edge cases before writing any code.

SetIt builds a trial component with internal input generation for testing and diagnostics for checking results.

LoopIt runs a feedback cascade: write code, check results, write code, check results, until it works.

DeliverIt extracts the clean, final component, without the input-test and diagnostic parts.

02 / how to install

Download once, then hand over to your agent

Download RobohopperInstaller.rhp using the button above.
Drag the file into Rhino 8 and approve the download. The installer retrieves Robohopper from Rhino's official package server and opens setup.
Complete the Robohopper setup window and choose the workspace your agent will use. The installer places the bridge, kit and skills together.
Open that workspace with your AI agent and paste the starter prompt above.
Open Grasshopper when the agent asks. The bridge starts automatically; then ask the Robohopper skill to build your definition.

Full guide: help and getting started.

03 / local, cli-only, yours

Your own agent drives it, on your machine

CLI only, no MCPTwo local servers on 127.0.0.1 (5200 authoring, 9999 canvas); your agent drives them over local HTTP. Requests to the authoring bridge without its per-session token are rejected before dispatch. No outbound calls of its own.

Install and goAuto-starts with Grasshopper. Nothing to place on the canvas, no command to type.

Your own AIBring the agent you already use. Robohopper is the substrate it drives, not a chatbot.