Omnigraph is an open-source object-storage native graph database with branching and typed ontology. It allows AI agents safely collaborate on shared knowledge. Give agents one typed graph with Git-like branching, review, and merge for every write, so changes can be validated before becoming shared context. Run it on your own S3-compatible storage, with semantic, keyword, and hybrid search plus graph traversal in one query. No hosted memory API or proprietary storage required.