1Password CLI - op item create Custom field

PS C:> op.exe item create --category=`"Test`" --vault=`"Tester`" --title=`"$Title`" `"Sharepoint link[URL]=$SharepointLink`" `"Username[Text]=$Username`" `"Password[Password]=BigBadPassword1`"

Creates the item fine, but the Sharepoint link field is missing. I have tried omitting the [text], same thing. Tried changing [URL] to [Text], same thing. Tried using `"Sharepoint link=$SharepointLink`" `"Sharepoint link.fieldType=text`" also, but it just creates the field, empty. I can get it to exist, with a URL, by using '"Server.SharepointLink[URL]=$SharepointLink"', but then it exists in a section apart from the username and password, labelled server?!?

I can create what I want just fine via the app (below is an example of that being queried by op item get, but just can't figure out how to put in a darned simply text field using op!!

ID: <identifier here>

Title: <title here>

Vault: Tester (<identifier here>)

Created: 2 hours ago

Updated: 2 hours ago by <user here>

Favorite: false

Version: 1

Category: Test

Fields:

     url: https://example.com

     email: <e-mail here>

      password: [use 'op item get <identifier here> --reveal' to reveal]

What am I missing??