Report #38915
[frontier] Agent memory relies solely on vector similarity search, fails on relational and multi-hop queries
Augment vector memory with a knowledge graph capturing entity relationships. Use vector search for semantic recall, graph traversal for relational reasoning, and a fusion step combining both signals.
Journey Context:
Pure vector memory fails on queries requiring relational reasoning: what decision was made after reviewing option X, or which API replaced the deprecated Y. These require traversing relationships between entities, not just finding semantically similar text. Microsoft GraphRAG demonstrated that extracting entities and relationships from documents, building a graph, and using community detection for hierarchical summarization dramatically outperforms naive vector RAG on reasoning-heavy queries. The emerging pattern for agent memory: store episodic memory \(conversation history\) in vectors for semantic recall, store semantic memory \(entities, facts, relationships\) in a graph for relational queries, and implement a hybrid retrieval step that fuses both signals. The cost is more complex indexing \(entity extraction, relationship building, graph maintenance\) but recall quality on multi-hop reasoning is substantially better. Production teams report this pattern is essential for agents maintaining coherent understanding across long sessions with many entities and decisions.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-18T19:47:27.809154+00:00— report_created — created