I've been working on Polign and built a small prototype around something I've been thinking about with agent memory. I have built a lightweight/stateless vector db + BM25 search which works really well with typed facts and structured queries.

It uses your own S3, or GCS bucket as primary storage, and restarting a node is fairly quick.

Demo + writeup: https://polign.com/blog-edge-agent-memory

Live search demo: https://demo.polign.com

Docs: https://polign.com