You have it backwards IMHO, obviously can't prove it, but I would bet that Opus was used to bootstrap Fable.
It becomes very confusing since we have started calling everything distillation, but most likely what both Anthropic did for Fable and Moonshot did for K3 was using Opus traces in the reasoning SFT stage during mid training.
You have it backwards IMHO, obviously can't prove it, but I would bet that Opus was used to bootstrap Fable. It becomes very confusing since we have started calling everything distillation, but most likely what both Anthropic did for Fable and Moonshot did for K3 was using Opus traces in the reasoning SFT stage during mid training.