Create Document Entry with Notes field

You're right that uploading files in Connect are not yet supported. And at the same time, having documents without attached files is also not supported, so creating 'partial' documents is not possible either. We are working on better file workflows in Connect and its SDKs.

What you can do now is create normal items in Connect, and then using the 1Password 8 betas, attach your files as fields. Another benefit there is that you can add multiple files to the same item, where as documents only correspond to a single file.

The error message you posted could be more clear on the fact that documents are not supported, I will report that to the team.