Tools & testing

You can develop most of a script without touching a radio. Pick the environment that suits the job:

Tool	Install	Best for
Web simulator	Nothing, it runs in Chrome	Quick tries, sharing a reproducible setup, loading a script zip
FrSky Suite	FrSky's desktop app	Simulator with a real folder on disk, installing scripts on a radio, backups
VS Code project template	VS Code, the Ethos extension, Python	Ready-made project: ▶ deploy to simulator or USB radio, live print() output, i18n, release zips from git tags
VS Code deployments		How that tooling works: USB HID, drive discovery, safe copying
ethos-tools + an AI agent	Node.js + a clone or Claude Code plugin	Letting Claude (or another agent) boot a radio, deploy your script, screenshot and drive it, and read its errors

Whatever you use, read Debugging for how to see print output and Lua errors.

A typical loop

1. Edit scripts/<yourscript>/main.lua in your editor.
2. Copy the folder into the simulator's radio directory. Delete any stale main.luac in it, because Ethos compiles main.lua on load.
3. Restart the simulator. Scripts only load at boot, and cached modules stay cached until a restart.
4. Watch the console for errors, then exercise the script.
5. When it behaves, test on the smallest screen you support (an X18 is 480×320), then on a real radio.