No backend / tools fail
Ensure the Hopper Code Backend component is on the canvas
and Rhino is running, then run /hopper-backend to refresh the
connection. If ports 5555–5557 are busy, the
backend should fall back to free loopback ports automatically and show the
profile path in the component log.
Invalid connection token
Restart the frontend after the backend has started so it can reread
the connection profile. If you are using manual endpoint env vars, also set
GH_ZMQ_TOKEN.
GH shows offline when Revit has focus (Rhino.Inside)
The plugin marshals Grasshopper work onto Rhino’s UI thread via
InvokeOnUiThread (not Idle). Keep Grasshopper
visible while the agent is working, or run /hopper-backend
after refocusing. Liveness checks use a lightweight ping probe
that does not touch the canvas. Older Rhino.Inside.Revit versions may still
limit background Grasshopper — RiR 1.27+ improves this.
Plugin did not install
Install the .NET 7 SDK,
then run pnpm run build:gh-plugin. On Windows, set
HOPPER_GH_LIBRARIES if auto-detect of the Libraries path fails.
Stale plugin after git pull
Force a full rebuild and copy, then restart Rhino.
node scripts/install-grasshopper-plugin.mjs --force