Mistral releases open weights for Large 4, its 1 trillion-parameter model for coding and cyber defense

French AI lab Mistral made Mistral Large 4, nicknamed "Le Chonk," publicly available on Thursday, publishing the weights on Hugging Face three weeks after an Oct. 6 preview. The 1 trillion-parameter multimodal model activates about 52 billion parameters per task and can be downloaded and run on an organization's own systems. Mistral says extra reinforcement learning since the preview lifted its Terminal-Bench 4.0 score from 28% to 41%, roughly tying China's GLM-5.3, and it is pitching the model as the strongest open-weight option built outside China for agentic coding and finding and patching security vulnerabilities. Closed models such as Anthropic's still lead overall, and VP of Science Pierre Stock acknowledged that once the weights are out, access can't be contained.