We don't have any staff that are able to investigate the API here and make changes. I would love to fix it up (add relevant values that are missing and create calls that provide results matching the browser experience). I would make time for that if I had the opportunity.

Our code was forked from an old version of Moebooru. No one but the owner has full access to it and last I heard he doesn't work with Ruby. Although, there have been recent updates, assumedly taken from parts of more recent versions.

In the past, I have requested and received single files of our code. But the owner hasn't seemed willing to share it in full, so I haven't pressed the matter.

I doubt your project will include the forums, but I'll mention it anyway. This could possibly apply to the comments as well.

As I recall, the API will return forum posts in order of date last edited and will not provide the original posting date. You can still sort them on the client side using the post ID after downloading all pages of posts. But if you want to provide dates, you'll just have to use the HTML version (parse it or include a web view).