Moonshot launches Kimi K3.1 Pro and K3.1 Pro Highspeed
AspireAI · Moonshot AI
Moonshot says its new Kimi K3.1 Pro matches the frontier on coding, and that the weights arrive November 4.
K3.1 Pro is a post-trained version of K3, Moonshot's 2.8-trillion-parameter model, with a 1M-token context window. It is live today on Kimi.ai, Kimi Code and the API. Moonshot reports 65.7% on Terminal-Bench 4.0, just behind Claude Opus 5.5 at 66.4% and ahead of GPT-6 Astra at 58.2%.
Think of it as the same engine with a much longer pit crew behind it. A Highspeed variant runs 2 to 3 times faster, at double the API price.
One caveat: those benchmark tables are Moonshot's own. The independent Artificial Analysis index puts K3.1 Pro at 55, fourth of 215 models. And "by November 4" is a promise, not a file on Hugging Face.
https://www.kimi.ai/blog/kimi-k3-1-pro
Read the story and explore more from the AspireAI community.
Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.