Yes, typesafe config is an external library rather than using the built in interpreter. That is extra code.

If you wanted to do things in equivalent lisp style, you'd just compile a Config.java/Config.scala file and add it to the classpath. That's only a few extra lines in your ansible script. Your configuration will be statically typedchecked - failure to include a required parameter or including a param of the wrong type will result in a compile failure.

This is unconventional but a very reasonable way to go. At the moment I'm just using typesafe config because it's more or less the standard, but the more I think about it the more I like the idea of compiling my config.