My solution to this (not yet integrated) is to use a faster / cheaper model to process all the text first and see if it's actually relevant or not, before running the summarization / task prompt with the main model.
I realized that this is essentially a semantic search engine for text. Using the same principle you can feed a very large text file in, ask it a question, and it finds the page that answers that question.
This would be useful as a layer "beneath" the internet research agent, that it could use to sort through all the noise and answer the question.
https://gist.github.com/avelican/58958a2cf2b7e9f9f555ab94549...
It gives a lot of false positives, I'm not sure if this is a limitation of GPT-3 (have not tried GPT-4 for this yet, a bit too expensive for searching books) or a limitation of my implementation.
It's probably slower and more expensive than just using a vector db, I haven't tried those yet.