Can I take a look at app-picker.coffee?

well, neither of them is very well documented because we are focusing really hard on the JavaScript ecosystem right now. You can look at some example usage of watch.json here: https://glitch.com/edit/#!/create-react-app-sample and a glitch.json usage example is here: https://glitch.com/edit/#!/go-revel and https://glitch.com/edit/#!/ponylang-demo