OpenAI-backed legal tech firm pivots to Chinese Kimi K3 open-weight model

A US artificial intelligence start-up backed by OpenAI has built its first in-house model on Chinese lab Moonshot AI’s Kimi K3, highlighting a growing shift by Western tech firms towards Chinese open-weight systems amid soaring development costs.

San Francisco-based legal tech provider Harvey, whose high-profile backers also include Sequoia Capital and Andreessen Horowitz, said on Thursday that its new model, Harvey Tenet, was post-trained on top of the open-weight Kimi K3 base.

The company said the system achieved “state-of-the-art” performance in complex legal work.

The release marks a significant departure for Harvey, which serves major international law firms and enterprise clients. The start-up previously focused on customising closed proprietary models from US leaders such as Anthropic, OpenAI and Google for legal applications.

Harvey’s pivot was “a great example of open-weight models” enabling developers to post-train systems on specific industry or corporate data for higher accuracy and lower inference costs, AI policy researcher Simon Hedlin wrote on X on Friday.

Post-training is the process of refining a general-purpose base model with specialised data sets to excel at specific tasks.