Memento appears to be a legitimate memory plugin, but it needs review because it stores chats by default and has several paths that can send or reuse memory data more broadly than the local/privacy framing suggests.
Install only if you are comfortable with local long-term storage of conversation history and facts. Keep autoExtract and autoQueryPlanning off or use a local Ollama model if data must not leave the machine, disable crossAgentRecall if agents should stay isolated, review migration/deep-consolidation paths before running CLIs, and protect or periodically delete the ~/.engram data store.