[pron]

> a value can be checked against a spec on demand, but makes zero guarantees as to what that value does in other parts of a program

The spec is just metadata. How it's used is part of the tooling. I see nothing precluding using specs in tools that employ and analyze that information in different ways.

[aconz2]

Yep you are totally correct. I only point this out because the tool presented here does not do the same thing as other contract systems, but could (as you say) be used as a building block to get there.