The memory-systems frontier

The drop-in agent-memory default. Mem0g (graph variant) took the multi-hop agent-memory benchmark lead at 68.4% LLM Score in April 2026 — the flat-vector vs graph-memory architectural debate now has clear empirical evidence on the graph side for multi-hop tasks.

Architecture: Vector retrieval + implicit consolidation; Mem0g variant adds graph reasoning. 20-line config integration; the friction-minimum memory framework.

Reached 1.0 in early 2026 with stable Neo4j integration and a polished agent-memory API. The OSS counterpart to Zep is now production-ready for teams that want full local control over graph memory without the hosted-service dependency.

Architecture: Temporal knowledge graph over Neo4j. Multi-hop reasoning over consolidated agent memory; the right pick when 'what did Bob decide three sessions ago and why' is the shape of question.

OS-style explicit agent memory. v0.7 (April 2026) shipped genuinely usable explicit-memory hierarchy — the architectural opposite of Mem0's implicit consolidation. Pick Letta when deterministic memory state matters and the agent needs to reason about its own memory.

Architecture: Working memory + archival memory + explicit paging. The agent itself decides when to archive, compress, evict — different abstraction from vector-similarity-only memory frameworks.

Production single-node vector DB. Best ops surface in the category; PQ quantization makes it the right pick for storage-constrained deployments. Standard upgrade path from LanceDB when single-workspace scale crosses ~500K vectors.

The embedded-first vector store. Single-folder Arrow files; no server process to firewall. Default for offline / single-process deployments; scales further than Chroma before needing a server. The right vector backend for the /stacks/offline-rag-workstation recipe.

Hosted temporal-knowledge-graph memory product. Strongest API in the category for hosted scenarios; the OSS core lives but the canonical experience is the cloud product. Pick Zep when cross-machine continuity + multi-hop reasoning matter more than full local control.