On the other hand, in a codebase where test coverage is poor and average tenure of engineers is ~1yr, a significant impediment is getting the initial test scaff

On the other hand, in a codebase where test coverage is poor and average tenure of engineers is ~1yr, a significant impediment is getting the initial test scaffold set up; maybe I don’t know how to build factories for all the incidental inputs required to test my code, but I do know how the code itself should behave. If LLMs can help you to scaffold a test, and make it easy for you to write the business logic validation, I think that would be a big win. On the other hand, if the generated tests are like most UTs, they will be over-coupled to the implementation and therefore slow down development. You might even see folks start deleting all the tests and regenerating them as part of a big diff, if it’s too hard to fix individual test cases that are failing due to coupling rather than any logic issue.