The program changes the outputs only through the niri socket. It does not read the niri configuration file and does not write to it, so a file that a user or a tool such as home-manager controls stays correct. The design follows three properties of the protocol: - One connection accepts many requests, so the client opens one connection and keeps it. - A request for the event stream takes the connection, so the events need a second connection. - The event stream carries no event for a change of the outputs, so a program cannot wait for a monitor to connect. The watcher therefore reads the outputs at a regular time, and it reads them again immediately after any other event. The compositor moves the workspaces when a monitor connects, and that movement gives an event. The regular reading gives the guarantee, and the event gives the speed. The client separates a change that the compositor applied from a change that it kept for an output that is not connected. The second gives no result on the screen, and the interface reports it. The live test drives a running niri instance. It does nothing when the DYNAMONIX_TEST_SOCKET variable is empty, because it changes the outputs.