Memory Type Taxonomy overview

Memory Type Taxonomy as a cross-cutting topic — the classification of agent memory into distinct types with different persistence, update, and retrieval semantics. The four-type model (popularized by memories.sh) identifies: session memory (volatile, cleared per run — equivalent to context window scratch space), semantic memory (persisted facts and preferences — the "what I know" layer, typically memory.md), episodic memory (dated logs of past interactions — the "what I did" layer, supporting retrospection and audit), and procedural memory (workflows and reusable task patterns — the "how I do things" layer). This taxonomy maps to cognitive psychology's memory model (working memory, semantic long-term memory, episodic long-term memory, procedural long-term memory) and provides a principled framework for deciding what to persist, where, and for how long. Different agent products emphasize different memory types: Claude Code primarily implements semantic memory (MEMORY.md), Cline emphasizes structured semantic categories, and memories.sh is the only system that explicitly models all four types.