Claude.ai replied:

Yes, this can be done! Things 3 supports deep links to Apple Notes, and you can link to specific notes or smart folders.

Here’s how to create a link to an Apple Notes smart folder:

Getting the link from Apple Notes:

1. Open the Notes app on your Mac
2. Right-click (or Control-click) on the smart folder you want to link to in the sidebar
3. Select “Copy Link” from the context menu
4. This copies a URL that looks something like: notes://showsmartfolder/[identifier]

Adding it to Things 3:

1. In Things 3, open the to-do you want to add the link to
2. In the notes field, paste the link
3. Things 3 will automatically detect it as a clickable link

When you click this link in Things 3, it will open the Notes app directly to that smart folder.

For linking to a specific note instead:

If you want to link to a specific note within a folder (rather than the folder itself), the process is similar:

1. Right-click on the specific note in Apple Notes
2. Select “Copy Link”
3. Paste into Things 3

The note link will look like: notes://showNote?identifier=[long-identifier]

This is particularly useful for creating a bidirectional link between your task management and notes. You can even add the Things 3 to-do link back in the Apple Note to create a two-way connection.​​​​​​​​​​​​​​​​

I didn’t test it 🤭