Claude Code memory: how to manage context windows across long sessions

Claude Code memory: how to manage context windows across long sessions If you've used Claude Code for more than 30 minutes on a complex project, you've hit the wall: the context window fills up, Claude starts forgetting earlier decisions, and you get contradictory behavior. Here's exactly how I manage this — and the CLAUDE.md tricks that make long sessions actually work. The problem: Claude Code's memory is a sliding window Claude Code doesn't have persistent memory. It has a context window — a fixed amount of text it can "see" at once. On long sessions: Early decisions get pushed out of context Claude forgets constraints you established 2 hours ago You get contradictory code that breaks earlier architecture Worst case: Claude starts refactoring things you explicitly told it not to touch This isn't a bug. It's how transformers work. But it's completely manageable once you understand it. The 3-layer memory system I use Layer 1: CLAUDE.md as permanent memory Anything that must survive th