stylus/stylus ? reverse-engineered prompt

Build me a Node.js package and command line tool for working with Stylus files, so I can write styles in Stylus and compile them into CSS. It should support the indented Stylus syntax as well as normal CSS style syntax, and I want a simple workflow where I can point it at a .styl file, watch for changes, and output a .css file.

Please make it feel like a real, usable compiler with decent error messages, a clean API for using it from JavaScript, and a CLI that works from the terminal. If there are any current best practices or docs I should follow, look them up online and use them. Also include enough tests so I can trust it works on common Stylus features.