This was a really great blog post. I'm taking a look at your world examples to attempt to play with it and hobble something together from scratch for my own world.

Dumb question: under the "Object Types" of the "Utilities" section of the world, readable-actions and readable-commands appears to be defined twice, first as list, then as append/build-action.

I am unfamiliar with Guile's conventions, but why are things declared in this manner?