Comment by deaux

The only time I've ever seen this happen is when you give it a massive codebase, without any meaningful CLAUDE.md to help make sense of it and no explicitly @ mentioning of files/folders to guide, and then ask it for something with huge cross-cutting.

> spanned a couple different codebases

There you go.

If you're looking to prevent this issue I really recommend you set up a number of AGENTS.md files, at least top-level and potentially nested ones for huge, sprawling subfolders. As well as @ mentioning the most relevant 2-3 things, even if it's folder level rather than file.

Not just for Claude, it greatly increases speed and reduces context rot for any model if they have to search less and more quickly understand where things live and how they work together.