Letta memory blocks persist across interactions and are included in each prompt without retrieval. Multiple agents can share a block, with read-only policies separated from editable work state to make update boundaries explicit. AgentFile exports and imports prompts, memory, tools and conversation history, and can create a fresh initial state for each evaluation. Secret values are cleared on export, and moving to another framework may require adapting its memory concepts. Persistent memory does not mean unlimited context or automatically safe collaboration.