It appears that Mastodon uses Oembed to fetch content for posted links. Is there some other method to simply get a content excerpt and image, a bit like with Open Graph or Twitter Cards ? Perhaps Mastodon could also try to find one of those in meta/headers as many sites use them and they provide an much simpler solution for url description.
It appears that Mastodon uses Open Graph as a fallback.
A post was split to a new topic: How to compose links?