No idea whether you intend to support Windows or not, but in any case I thought I'd point out that the tests currently fail on Windows due to Unix-specific paths, among other things. (The first failure is here: https://github.com/segmentio/metalsmith/blob/eb43dfdb3fc7ccd5f9c7b1b501819c07cea8d162/test/index.js#L71-L74). Eh, I guess I'll spin up a Vagrant VM for now.