Compose into a host

Super Harness composes as a plugin alongside your app surface. It adds the harness.* requests and four typed collections without creating a second server or socket.

Your host must merge harnessContract(), provide one collections backend, return a stable user principal from identify, and include harness(engine) in its plugins.

const host = defineContract({
  plugins: [harnessContract()],
  shared: defineSurface({ clientToServer: { /* your handlers */ } }),
  roles: { user: {} },
})

The host's implement() call only provides its own handlers. The plugin owns every harness.* handler.