Each day, OpenClaw auto-creates a file at memory/YYYY-MM-DD.md for that date. These daily files capture session-specific context: what you worked on, decisions you made, problems you hit. At session start, OpenClaw loads today's file and yesterday's file so the agent has recent context.
Older daily files stay on disk but aren't loaded into the prompt automatically. You can still reference them by asking the agent to read a specific date. After 30 days, you can archive or delete old daily files without affecting long-term memory in MEMORY.md. Think of them as a work journal that the agent reads over your shoulder.