Keep Mac Awake During Long Tasks Using Caffeinate

This skill keeps a Mac awake using the built-in caffeinate command, with no install needed, so a long supervised task, build, download, or automation run isn't interrupted by sleep.

Use it when the user wants the Mac to stay awake during a long supervised task, or when a build, download, or automation run should not be interrupted by sleep. It is adapted from davidondrej/skills; local paths, tools, credentials, and agent features should be verified before acting, and commands, remote access, scheduling, browser automation, or file-changing workflows need explicit user approval and a confirmed target environment first.

The standard command is caffeinate -d -i -t <seconds>, with duration in seconds (2h = 7200, 7h = 25200, overnight/9h = 32400) - default to -d -i -t <seconds> unless told otherwise. Flag effects: -i prevents idle system sleep only (the screen may still dim or lock); -d prevents display sleep (screen stays on); -d -i is the default choice, screen on plus system awake; -d -i -s adds -s, which only works while plugged into AC power; -u -t 1 simulates user activity to wake the display immediately. Instead of a fixed timer, it can tie to a process: caffeinate -d -i -w <PID> stays awake until that process exits, or caffeinate -i npm run build wraps a command and exits when it finishes. It should run visibly in the user's own terminal pane (via cmux send, reading the cmux skill first) so it's easy to Ctrl+C, or as a background Bash task - never blocking the foreground shell. To verify it's running: pgrep -fl caffeinate (shows exact flags), ps -o etime= -p <PID> (how long it has run), and pmset -g assertions | grep -i deny (confirms sleep assertions are active). To stop it early: pkill -f "caffeinate -d -i" or Ctrl+C in its pane.

caffeinate -d -i -t 7200    # full power: screen stays on + no idle sleep, for 2 hours

Built entirely on macOS's own caffeinate, pgrep, ps, pmset, and pkill tools, with no third-party dependency. Named gotchas: caffeinate prints nothing and holds the prompt - it isn't stuck, verify with pgrep rather than by staring at the terminal; with -t it exits silently on expiry with no notification, so check pgrep rather than assuming it's still running; and caffeinate cannot keep the keyboard backlight on, since the backlight has its own inactivity timer with no CLI or API on Apple Silicon - the only fix is manual and one-time, via System Settings > Keyboard > "Turn keyboard backlight off after inactivity" > Never.

Anyone running a long, unattended Mac task - a build, download, or automation run - who needs the machine to stay awake without installing anything, and who should confirm afterward the exact PID, flags, and wall-clock expiry time.