I highly recommend having fairly succinct project level CLAUDE.md files, and defer more things into sub-folders. Use the top level as a map. Then during your planning of a feature, it can reach into each folder as it sees fit to find useful context to build out your phased implementation plan. I have it use thinking mode to figure out the right set of context.

At the end of each phase, I ask claude to update my implementation plan with new context for a new instance of claude to pick it up. This way it propagates context forward, and then I can clear the context window to start fresh on the next phase.