It would be good to be able to create a new CDI extension. A basic command could just be :

cdi-new-extension --named MyExtension

This will generate the following code as well as enabling :

class MyExtension implements Extension {

}

The extension could be enabled with just an attribute :

cdi-new-extension --named MyExtension --enable=true

This will create the META-INF/services/javax.enterprise.inject.spi.Extension file and would declare the extension within the file.