> I find it interesting that generally the first instinct seems to be to use LLMs for writing test code rather than the implementation. Maybe I've done too much TDD, but to me the tests describe how the system is supposed to behave. This is very much what I want the human to define and the code should fit within the guardrails set by the tests.

I feel the same way about how test code is viewed even outside of AI. A lot of the time the test code is treated as a lower priority code given to more junior engineers, which seems like the opposite of what you would want.