Whoops, I should’ve checked the docs before asking! What I am looking to recreate is the pureCompiler: https://github.com/typelevel/cats/blob/master/docs/src/main/tut/datatypes/freemonad.md#6-use-a-pure-compiler-optional So I guess I actually meant was a combination of

Free

and

State

. But I think I can put it together now, those examples shed some light on how to mix Free with more advanced types.