This already exists on Reddit as a bot that says “the best I did was reducing this article by 87%, here it is…”

I imagine you just need to wrap that in a browser plug-in. Or maybe already exists.

This is done by autotldr[1] which is powered by smmry[2]. Smmry is pretty neat actually !

[1] http://autotldr.io/

[2] https://smmry.com/

Sadly it seems to fail bad on things that aren't new articles.

Try for example https://en.wikipedia.org/wiki/Functional_programming/ as an input to smmry - you don't get the idea

I mean, it works ok. I think the issue here is structured documents like that wikipedia article. If you used smmry on each section, leaving the headers and structure alone, you'd probably get a far more 'coherent' result, and it's not surprising that the tool is built for "single block" content.

It would probably not be very hard to build a mediawiki smmrly extension that does just that.

It exists in various forms and you are not the only one that desires this.

https://tldrthis.com/

https://www.summari.com/products/chrome

Etc etc

title, subtitle, and thesis statement from each paragraph.

We're testing something that addresses this need right now. Email me if you wanna try the beta (amit @ sudowrite)