Sentinel

Multi-tenant control plane that brokers requests between agents and downstream MCP servers: server registration, a default-deny role-based policy engine, an encrypted credential vault, audit logging, and an OAuth 2.1 proxy for upstream MCP servers. The commercial effort was sunset once well-funded competitors (Runlayer, golf.dev) entered the same space; the core was open-sourced instead, as a self-hosted governance layer anyone can run.