Hi @brad.bylls .
Here is how to get a list of registered keyboard shortcuts (hotkeys) that I know of.
Run the following text command
HotKey.Export
This will export the list in json format.
For the exported file, run the following text command
Paths.Get
You will see a lot of paths, but look at the "cloudCacheDirectory" folder.
You can use @JeromeBriot add-in "Fusion 360 Open folders" to easily open the folders.
https://github.com/JeromeBriot/fusion360-open-folders
The file "hotkey.json" in the folder is a list of Hotkeys.
Make sure that the CommandID you want to check is in this file.
Also, I haven't checked, but when you execute the addButtonDefinition method, do you set the resourceFolder?
https://help.autodesk.com/view/fusion360/ENU/?guid=GUID-04eb6198-72cd-4430-a6a4-8d68a1105b8e
If not, you may not be able to register it with Hotkey because it cannot be pinned.