What actually happens at sleep

When a Mac sleeps, the CPU stops running your processes. The agent is not killed. It is frozen. When the machine wakes, the process continues. By then the API connection it was using has timed out. The tool call it was in the middle of has failed. On a laptop, a closed lid means sleep within seconds unless something prevents it. A lock screen does not cause sleep. A screensaver does not either. Only the sleep timer and the lid do.

Fix 1: caffeinate for a single task

macOS ships a tool that holds the machine awake while a command runs. Start the agent through it and the Mac stays up until the agent exits.

caffeinate -i claude

The flag keeps the system from idle sleeping. Add a second flag to keep the display on too, which matters only for tools that drive the screen.

caffeinate -di claude

This does not survive a closed laptop lid. The lid switch overrides every idle assertion. It also does nothing after the agent exits and you start the next task without it.

Fix 2: turn off sleep for the machine

On a desktop Mac, or a laptop on power, set the sleep timer to never and leave it. These are the settings we use on every agent Mac.

sudo pmset -a sleep 0
sudo pmset -a disksleep 0
sudo pmset -a displaysleep 10
sudo pmset -a womp 1

The display can still sleep. That saves power and changes nothing for a terminal process. The last line enables wake on network, which helps if something does put the machine down.

That covers the quick fixes. The full guide also covers the closed lid, keeping the terminal session alive with tmux, coming back after a reboot, and when a laptop is the wrong machine for an always-on agent: read the full guide on macrun.dev.

Full disclosure, I run MacRun, which rents dedicated Mac minis for builds and coding agents.