Currently when sharing a documentation(Article or Tutorial), the url is render as a pure title card.
If there is image information available, we should add og:image to html header to better render the doc link in other site.
Issues is tracked on
For reference, I've just run into this issue as well with the WWDC Notes project. I've migrated the old site to DocC this year, but when I post session notes on social media (Twitter, Mastodon, etc.) there's no preview like it used to have on the old website. That's a bummer and if there's anything I can do to help get this done, let me know.
See for example this tweet linking to this note. Note that I've decided to take screenshots of the site and attach that as there are no cards showing, which is annoying because I can't automate that. I'd like to post these tweets automatically when new notes have been added with a rich preview, if possible.
Thank you for your consideration and hard work! DocC is awesome. 