# Harvey previews Tenet, its first own legal model, post-trained from Kimi K3

Canonical page: https://technooptimist.io/stories/harvey-previews-tenet-its-first-own-legal-model-post-trained-from-kimi-6ff4a238
Date: 20 Aug 2026
About: [Harvey](https://technooptimist.io/companies/harvey.md) · [Harvey agents](https://technooptimist.io/ai/harvey-agents.md)
Original source: https://fireworks.ai/blog/post-training-kimi-k3-with-harvey-for-long-horizon-legal-work

Harvey and Fireworks AI used reinforcement learning on long legal tasks to post-train Moonshot's open-weight Kimi K3 into Tenet. It completes almost twice as many held-out LAB tasks as the base model at about the same cost. Harvey had relied on OpenAI, Anthropic and Google models until now.

## Key facts

- LAB all-pass rate 19.7% vs 10.8% for base Kimi K3.
- Tens of thousands of practice runs per checkpoint, each over 50 turns and 100,000 generated tokens.
- Gains carried over to tests it was not trained on: Mercor Apex Agents (corporate law) 58.8% to 74.0%.
- Cost $5.92 per LAB task vs $5.62 for the base model.

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