The second sentence of your summary is fine, but I don’t like the first sentence:
> Use your language’s type system to parse unstructured inputs.
We don’t use the type system to parse. We use the type system to provide evidence (also called a proof or a witness) that parsing was successful, and we rely on the language’s access control facilities (public/private) and the soundness of its type system to prevent fabrication of false evidence.
> Use your language’s type system to parse unstructured inputs.
We don’t use the type system to parse. We use the type system to provide evidence (also called a proof or a witness) that parsing was successful, and we rely on the language’s access control facilities (public/private) and the soundness of its type system to prevent fabrication of false evidence.