I am not sure that is bug.

#!/usr/bin/env node
const args = require('args')
args
.option('port', 'The port on which the app will be running', 3000)
.option('reload', 'Enable/disable livereloading')
.command('serve', 'Serve your static site', ['s'])
const flags = args.parse(process.argv)
I am not sure that is bug.

example script:
node app serve