I've had an idea for an automated verification for a while, but too busy to implement it.

For every property of the system, implement a mock that simulates a system that works, and multiple variations with forseeable bugs (models are fairly good at predicting possible bugs). Then, write a unit tests that pass on the working simulation and fail on the buggy simulations.

This way model ensures reasonably well that the unit tests test what they're supposed to. Then, you use those tests as a verification to guide the model to implement the functionality.

This approach relies on the assumption that the model can design a reasonable architecture composed of independently-testable modules. In my experience, frontier models should be able to do that.