Recursive self-improvement would be the model helping with the model research program. Coming up with hypotheses for training and architecture improvements, running experiments, interpreting the results, figuring out how to incorporate the best stuff into the next version, etc.

Where do you see evidence of vibe coding the harness? (and who are you talking about, Anthropic or the link I shared?)

It seems odd to complain about a AI coding tool being coded with AI. That's just eating your own dog food. In my opinion it makes it better, because the tool is very well tested.