Such an explainer would contain for example a simulation of the feature, where it shows how data flows between components and allows the reviewer to tweak parameters and see how it affects things. The explainer can visually show edge cases or introduce faults.
Basically my problem is that agents can write a lot. They can write a lot of code and also a lot of natural language design/spec which ultimately becomes hard to review (sloppificarion of design documents)
Sometimes you can tame this by focusing on very high level, human curated specs, but since often the devil is in the details, you need a way to see these details.
I found that interactive visual exploration tools are a very good way to both iterate on your problems and to share it with your colleagues.
Inspirations: