hub_kernel wraps a domain and connects it to a host app's infrastructure through named ports. It ships no domain of its own: each hub is hub_kernel wrapped around one domain.

hub_kernel-api gives any hub built on hub_kernel a JSON API: the host lists the hubs it serves, and every call goes through the host's sign-in, permission check and account scope.

hub_kernel-mcp serves the methods every hub a host serves exposes as MCP tools at one address, with every call going through the host's sign-in, permission check and account scope.