Claude Code quietly shipped something I've been waiting for: agents that learn between sessions. Not "memory" in the chatbot sense — actual persistent knowledge stores that agents write to disk and carry forward into future work.
There are two flavors. Auto memory is for the main Claude session itself. Subagent memory is for individual subagents you define. Both use the same architecture under the hood, and both are worth understanding if you're building anything with agents that needs to get smarter over time.
Auto memory is a persistent directory where Claude records patterns, insights, and project-specific knowledge as it works. This is different from CLAUDE.md files (which are instructions you write for Claude). Auto memory is notes Claude writes for itself.
