for personal use i created a LaunchDaemon to keep `caffeinate -s` running all the time

  /Library/LaunchDaemons/ze.caffeinate.plist

  <?xml version="1.0" encoding="UTF-8"?>
  <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
  <plist version="1.0">
  <dict>
      <key>Label</key>
      <string>ze.caffeinate</string>
      <key>ProgramArguments</key>
      <array>
          <string>/usr/bin/caffeinate</string>
          <string>-s</string>
      </array>
      <key>KeepAlive</key>
      <true/>
  </dict>
  </plist>