…is not so hip.
Is T142243 Add open graph meta tags the main task for this?
One extension for doing this is WikiSEO which handles Open Graph, Twitter Card, and basic other metadata (keywords, description, image, author, publisher, type, site name, locale, tags). It does it with a
<seo> tag whose contents are base-64 encoded in-place as HTML comments and then read out again when a page is loaded.
I guess the first step though is not for pages to provide extra metadata, but for the existing available metadata to be exposed in the right ways? So image, first paragraph, title, authors, article type, and maybe categories as keywords?
The Phabricator task is T13018.
Hand-curated descriptions are probably hopeless for MediaWiki; for wikitext-based pages the description should probably be provided by TextExtracts. Flow probably needs to provide OG tags on its own, and I’m not sure we care that much about Gerrit. I wonder what’s up with Commons though - that file page definitely did not have opengraph tags but Discourse oneboxed it anyway.
Having T12345 autolink to Phabricator would also be nice.
Related discussion focusing on Commons and with examples in the other Discourse testing site: https://discourse.wmflabs.org/t/onebox-commons/192
Filed as https://phabricator.wikimedia.org/T185017 for now.
When exactly oneboxing happens seems a bit hit and miss. For example Wikidata supports OpenGraph (T51859) and it indeed works when it is its own paragraph, OTOH GitHub links also work when they are in a separate line but not separate paragraph…