I have no idea about website summary.
When I share medium post to Microsoft teams or Discord or facebook.
It shows up a mini description with picture. How does it work?
>Solution :
Social media sites such as Discord & Facebook use the metadata from a web page to generate the link previews, such as the one in the image above.
Here is an example of the markup that you would use:
<meta property="og:url" content="http://www.nytimes.com/2015/02/19/arts/international/when-great-minds-dont-think-alike.html" />
<meta property="og:type" content="article" />
<meta property="og:title" content="When Great Minds Don’t Think Alike" />
<meta property="og:description" content="How much does culture influence creative thinking?" />
<meta property="og:image" content="http://static01.nyt.com/images/2015/02/19/arts/international/19iht-btnumbers19A/19iht-btnumbers19A-facebookJumbo-v2.jpg" />
You can use Facebook’s share debugger to test a page and see what the link preview would look like.