GPT-4 presumably.
The mozilla/readability library is a good first step though.
Edit: I'm thinking of something like LlamaIndex
Yes, I could try to figure out which bits of the page need to be sent along with the prompt, but that's hard in the general case. Squeezing a bit more out of the prompt window by stripping out unnecessary boilerplate is easy by comparison. (Multi-page articles are another headache).