Agent Memory Systems and Knowledge Graphs: Letta, Mem0, Graphiti, and Cognee (codepointer.substack.com) AI

The piece compares four long-term agent memory/knowledge-graph approaches—Letta, Mem0, Graphiti, and Cognee—showing how each handles storing, retrieving, and updating facts across sessions, from simple self-edited text blocks (Letta) to entity-linked vector memories (Mem0), bi-temporal typed fact edges (Graphiti), and an explicit extract-cognify-load pipeline that builds graph and vector stores (Cognee).