I'm starting small posts under the vocabulary tag, to tease out concepts that fall out of other posts, but would be too much of an aside there. This one line could go under "Jargon", to be fair. These may evolve to larger post. I am going to try and at least leave you with a question in each :-).
Synthetic Test Driven Development is when you have a coding agent generate the tests and the code, and also do the refactor step(s) with an agent.".
When considering Synthetic TDD it is worth considering what benefits you get from writing tests first as an activity, in a very short cycle, and what value you get from having tests as an artifact.