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Moonshot Launches Kimi K3.1 Pro With One‑Million‑Token Context and Highspeed Variant

The company says it reduced the model’s offensive cyber capability by removing cyber training data to balance wider access and safety.

Overview

  • Moonshot published Kimi K3.1 Pro as a long‑context model with a native one‑million token window and a Highspeed variant that it says responds two to three times faster, and the model is available through Kimi.ai, Kimi Work, Kimi Code and the company API.
  • Moonshot reported competitive benchmark gains, citing 65.7% on Terminal Bench 4.0 that it says approaches Anthropic’s Claude Opus 5.5 at 66.4% and outpaces OpenAI’s GPT‑6 Astra at 58.2%, and improved long‑horizon coding from 55.95% to 61.2% on its Kimi Code Bench.
  • The firm disclosed that it removed cyber‑related training data and tasks during development, which lowered its internal vulnerability score to 81% from 90.5% for an unredacted version, a choice Moonshot frames as a deliberate safety tradeoff.
  • Technical claims published with the launch describe a large architecture (reported ~2.8 trillion parameters), hybrid Kimi Delta Attention and a NoPE positional scheme to support the long context and runtime efficiency, but many specifics await independent verification after the weights release.
  • Releasing full model weights for public use will let developers self‑host and test the model offline, a move that could widen access and independent evaluation while raising questions about dual‑use risks and cybersecurity oversight.