The native backend's user commands as release entry points, for an app's <app>-ctl (macaw_host's generated script), on macaw_host's release protocol (Macaw.Host.Release):

• the arguments arrive as a JSON array of strings in <PREFIX>_CTL_ARGS, the password in <PREFIX>_CTL_PASSWORD, never on a command line;
• the output is one JSON object per line on stdout;
• a failure is one line on stderr, {"ok": false, "error": "…"}, and exit status 1; malformed arguments fail as Macaw.Host.Release says ("<PREFIX>_CTL_ARGS must be a JSON array of strings").

<PREFIX> is the app's :env_prefix (macaw_host's ctl description):

config :macaw_auth, Macaw.Auth.Native.Release, env_prefix: "MY_APP"

There is no default: without it, the entry points fail naming the setting. bootstrap/1 and user/1 take the prefix instead, for an app's release module to delegate to.

The app's Ctl.AppCommands runs them in a throwaway container of the image (bin/<app> eval, macaw_host's Ctl.Docker.eval_args/3), the password passed by name (-e <PREFIX>_CTL_PASSWORD), so they work with the app stopped:

eval_args(env, "Macaw.Auth.Native.Release.user()",
  [{"MY_APP_CTL_ARGS", JSON.encode!(["add", name, "--role", "admin"])},
   {"MY_APP_CTL_PASSWORD", password}])

That VM is not the app's node: a revocation (password, reset-second-factor) deletes the sessions, and the user's open pages leave at their next re-check.