[hollowpoint]

Ok thanks. I noticed both the Android and iOS Kindle apps have an export function for annotations that emails you an HTML file with the annotations data. It's pretty clean output, very predictable and compliant HTML. Plus the Kindle itself will email you the annotations in the form of CSV and PDF, as well.

Wonder if it'd almost be easier to write a plugin that consumes the HTML and CSV files, and import the annotations that way. Then you'd have no device connections to deal with, just the 2 file types for input options. One could use the Pandoc plugin to clean up the input or convert it to something else, before it gets stuffed into a Calibre custom column. As it's a one-way sync (it only imports the annotations to my knowledge, it doesn't look like they get synced back to connected devices), the option of importing file input only versus having to worry about app, device, and OS support, seems vastly simplified.

ETA: The problem with importing the HTML or CSV annotations output, I just remembered, is the fact that users can only export one book at a time. I haven't yet seen a way to "export all annotations from all books." If there was a way to do that, this would seem such a streamlined way to get annotations into Calibre.