Keeping a Mac awake while agents work

I had Amphetamine set to allow closed-display mode for a 24-hour session. The Mac still went to sleep when I closed the lid.

The power log settled it:

Five for five. Restarting the Amphetamine session had seemed to fix it because I often plugged the charger in at the same time. The charger was doing the work.

#The switch that survives battery power

Apple documents the limit in man caffeinate: -s creates PreventSystemSleep, and that assertion is valid only on AC power. Amphetamine is a sandboxed App Store app. It cannot run the root command that changes this behaviour on battery.

The command is undocumented:

sudo pmset -a disablesleep 1

I verified it by hand, then built agentawake around it.

Two root LaunchDaemons run. One checks for active agents every 30 seconds. The other stays attached to pmset -g pslog so unplugging the cable is handled immediately.

It tracks work, not open windows:

• Claude Code through the caffeinate child it creates during a turn.
• Codex through its Codex is running an active turn power assertion.
• Oh My Pi through its Oh My Pi agent session power assertion.

Sleep stays disabled for ten minutes after the last turn. On battery, normal sleep returns below 20%. It can resume at 25%, which stops the setting from flipping around one battery percentage.

The Mac is still fully awake with the lid shut. It drains and gets warm. The battery floor bounds that, but it does not make the private macOS setting safe or supported.

#Pager handles the visible part

The daemon can run silently, but I wanted to know when the cable came out, the battery floor tripped, or pmset refused the change. It uses Pager when Pager is installed.

Pager is another small macOS tool I built. Anything that can run a shell command can raise a native panel with text, charts, media, sounds, and action buttons. A button can run a command and return the answer on stdout. The panel never steals keyboard focus.

agentawake starts Pager as the logged-in user, never as root. If Pager is absent, sleep control keeps working and state changes go to /var/log/agentawake.log.

Both are public:

• agentawake
• Pager