Uploading large codebases is particularly useful.
I've found that I get better results if I cherry pick code to feed to Claude 3.5, instead of pasting whole files.
I'm kind of isolated, though, so maybe I just don't know the trick.
Part of how it does that is through ingesting your codebase into its context window, and so I imagine that bigger/better context will only improve it. That's a bit of an assumption though.