Agent running on a Mac mini (OS X 10.8.2) would go offline and not come back. When trying to ssh to the mini the connection would not complete. I had to wake the mini with a keyboard press and then the Agent came back online. Jobs backed up on the mini's queue while it was offline for an extended period of time.
We may not want to take any action in the code on this. But support should be aware that if customers install the Agent on OS X they may need to modify the settings in the Energy Saver control panel so that the Mac does not go fully to sleep. On my test system 'Wake for network access' was enabled but the Mac still did not wake on Skybot server requests or on my ssh request.
Tip - here's a command that will disable the power/sleep mode:
sudo pmset sleep 0