Persistent memory in Claude Code: what's worth keeping

Claude remembers nothing. Every session starts from scratch — the preferences you explained last week, the business constraints it discovered while working on the code, the corrections you had to make twice. Everything disappears with /clear. CLAUDE.md partially compensates: you encode project conventions, the stack, deployment rules. But there's a category of information CLAUDE.md handles poorly: things that evolve over time. An architecture decision made this month, a style preference corrected mid-session, a gotcha found in production. These have variable lifespans and don't all belong in a file versioned with the project. Claude Code has a persistent memory system for exactly this. What auto-memory does — and doesn't Auto-memory is a set of Markdown files in a dedicated directory per project (~/.claude/projects/<project>/memory/) or global (~/.claude/memory/). Claude reads them at session start via an index file MEMORY.md, and can update them during the session. What it doesn