The problem turned out to be an older copy of the app on my disk and macOS getting confused and looking in the wrong place. I'm adding a Widget to an existing app that doesn't currently have one. I have the current, App Store version in /Applications. I've been running the updated version from Xcode or exporting it to my desktop and running it from there. The Widget itself -- as noted in the question -- runs just fine. But it seems that when looking for the Intent used for the configuration, it prefers to look in /Application rather than the Xcode version. As soon as I deleted the original app, the widget and its settings immediately started working.

I asked the same question about Intel Macs: https://developer.apple.com/forums/thread/659420?answerId=637749022#637749022 Currently one person saying that it works, but I still have not had any luck.

This is still not working for me. Clearly I'm doing something different to Hiren, so to be clear, here are the steps: Create a new Mac project Add a new Widget target Change the generated Intent, adding a parameter. You also need to add a "Siri Dialog Prompt" Click "Run" Click "Info" in the Widget Simulator Click "Configure Intent" I don't see my optional parameter. When I click "Done" it says "Unable to Load." Back in my main project, the exact same Intent and Widget works just fine on iOS and iPadOS. Is there an extra step for the Mac? Is there a bug? I'm running Big Sur b9 and Xcode 12.2b2 now.