OpenCrab

MetaOntology OS integration for ontology-structured agent environments.

OpenCrab exposes the MetaOntology OS grammar through MCP, enabling ontology-based knowledge representation across nine semantic spaces (subject, resource, evidence, concept, claim, community, outcome, lever, policy). The server provides tools for ontology management, graph querying, relationship-based access control (ReBAC), impact analysis, and lever simulation. It integrates with Neo4j for graph storage, ChromaDB for vector search, MongoDB for document storage, and PostgreSQL for policy management.