A Memory Is Not a Transcript
The problem
A transcript preserves what was said; a memory system must decide what kind of thing it is preserving. LangChain’s taxonomy separates semantic facts, episodic experiences, and procedural know-how, while Letta’s memory blocks make some selected information editable and persistently present in the agent’s context. These are useful design distinctions, not settled categories: a correction about a user’s preference might also encode an episode, and a repeated successful workflow might become a procedure.
The tension is practical. Different representations invite different write and retrieval rules, and a system that treats every past interaction as the same kind of memory risks either losing useful structure or overfitting to a taxonomy. Once we ask what belongs in memory, the next question is who—or what—gets to change it.
Readings