It's telling that in their release post, Moonshot themselves said that K3 lags Fable and GPT-5.6 in "user experience". I took that to mean the stuff you can't push directly via RL, what some people call "big model smell".

"Despite being a highly competitive model overall, K3 nonetheless exhibits a noticeable gap in user experience compared with Claude Fable 5 and GPT 5.6 Sol."

https://www.kimi.com/blog/kimi-k3