Moonshot open-sources Kimi K2: 1T parameters, 32B active, modified MIT
Moonshot AI released Kimi K2, a Mixture-of-Experts language model with 1.04 trillion total parameters and 32 billion activated per token, pre-trained on 15.5T tokens and released under a Modified MIT license. Both Kimi-K2-Base and the post-trained Kimi-K2-Instruct checkpoints went up on Hugging Face with the weights downloadable, alongside an OpenAI and Anthropic-compatible API and a technical report. The architecture follows DeepSeek-V3's multi-head latent attention design but widens to 384 experts selected eight per token, uses a new MuonClip optimizer, and starts with a 128K context later extended to 256K.
The point is agentic tool use, not chat. K2-Instruct scored 65.8 on SWE-bench Verified and 66.1 on Tau2-bench in a single attempt with no extended thinking — numbers that put an open, downloadable checkpoint in the same band as closed models from months earlier, at roughly $0.60/$2.50 per million input and output tokens on Moonshot's API. The license carve-outs matter too: free commercial use is capped at 100M monthly active users or $20M monthly revenue.

WHY IT MATTERS
If you are building an agent harness, you can now fine-tune and audit a trillion-parameter checkpoint that trades near closed-frontier tool-use scores for a per-token price roughly an order of magnitude below the hosted frontier. That changes build-versus-buy economics for evaluation, distillation, and on-prem deployments where sending code to a third party is a non-starter — and it compresses the old rule of thumb that open weights run six months behind to a matter of weeks.
