> Today, an agent can chew through years of history and artifacts on a large codebase in a half hour, documenting as it goes, and have way better understanding of it than I ever will.

At my last job we worked in a large, but publicly available code base. My experience was that just giving an agent the prompt to look at area X to figure out how it works would use up half or more of the context window. And that was thrown away every time we started again. We had docs, agent generated overviews but the agents still filled their context windows way too quickly to actually really be any use.