Three-Tier Agent Memory Architecture with Multi-Scope Tagging: Episodic + Semantic + Procedural Memory with user_id/agent_id/session_id Scoping for Production Retrieval

Mem0·high signal

The 2026 production consensus for AI agent memory is a three-tier hierarchy: episodic (what happened — conversation history), semantic (what is known — facts, preferences), and procedural (how things work — workflows, patterns). Every memory write should be tagged with identity scopes: user_id for cross-session persistence, agent_id for agent-specific facts, run_id/session_id for conversation scope, and app_id/org_id for shared organizational context. At retrieval, scopes compose automatically. The recommended retrieval algorithm fuses three parallel scoring passes — semantic similarity, BM25 keyword matching, and entity matching — which delivers +29.6 point improvement on temporal reasoning and +23.1 on multi-hop queries over single-signal approaches.