Created some custom Pushbullet actions for KM so I can send messages to my phone. Thought others might find this useful. This contains two actions, one to send a message via Pushbullet, and another to send a URL.
AppleScripts can also access the environment variables using the system attribute command, but note that system attribute is not safe for international characters.
Read the variables via AppleScript requests to the Keyboard Maestro as described.