Hindsight

Hindsight is Vectorize's open-source memory system for AI agents. An LLM extracts facts, entities and timestamps from conversations and stores them in Postgres. Recall combines semantic, keyword, graph and time-based search and reranks the results. A reflect operation consolidates stored memories into observations and "mental models" that evolve as new evidence arrives. This consolidation sets it apart from Mem0, which extracts and stores the facts it judges most relevant. Hindsight maintains a separate memory bank for each user or agent and can be self-hosted or used through the managed Hindsight Cloud service. Agents connect to it through SDKs, framework integrations or an MCP server.

Hindsight is particularly useful for custom-built agents that need memory across sessions. One of our teams used it in a hackathon project to give agents per-user memory that improves over repeated sessions. Hindsight also has plugins for coding agents such as Claude Code, although those agents already have their own mechanism for retaining memory across sessions. The vendor reports leading scores on the LongMemEval benchmark, which tests recall over long chat histories. Teams building agents that need long-term memory for each user should compare Hindsight with Mem0 and measure whether its recall and consolidation capabilities improve agent behavior enough to justify the additional LLM calls and infrastructure.