Long-term memory stored as entities, relations and observations. Your assistant can remember your projects and preferences, and recall them next week. The reference server keeps a JSON file on one computer. This one is the same memory in Claude Code, Cursor and every other client you connect, on any machine. Tools: create_entities, create_relations, add_observations, search_nodes, open_nodes, read_graph, delete_entities, delete_observations, delete_relations.