Say I've X documents what algorithm/library/tika config/nekohtml filter would tell me which of those is an "article" and which is not, and for those that are give me the article text (i.e. w/o other surrounding text).

By an article I mean a chunck of structured text comprosing at least one paragraph, and I think most human readers can filter those out.

The easiest way I thought of is ensuring that doclength > Y, where Y would be 350 words for example.
But that's not the most reliable of ways, since there could be very long lists for example, and it doesn't give me the article text.
Looking for  tags, is not good enough.