Mistral released the open weights of Mistral Large 4, nicknamed “Le Chonk,” on October 29, after previewing the model on October 6. The company presents the release as a stronger open-weight option for coding and defensive cybersecurity. Its reported benchmark gains are notable, but they should be read as task-specific results—not a verdict that the model leads every workload.
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What changed after the preview?
Mistral says additional reinforcement learning lifted Large 4’s Terminal-Bench 4.0 score from 28% in the preview to 41% in the released version, a 13-percentage-point increase.
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31 The company’s reported Artificial Analysis Coding Agent Index score is 48%, tied with GLM-5.3; reporting also says Large 4 used 47% fewer tokens per task in that comparison.
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Those figures describe specific evaluations. They do not establish performance across all programming work, or show that a lower token count automatically means lower total operating costs. The available reporting also does not provide a substantiated, like-for-like numerical comparison with Anthropic’s Mythos 5.1.
A trillion-parameter multimodal model
Mistral’s documentation describes Large 4 as a multimodal mixture-of-experts model with 1.05 trillion total parameters and a 1.6-billion-parameter vision encoder.
17 The parameter count needs a little context: the Hugging Face model description lists 49 billion active parameters per token, or 52 billion when embeddings and the output layer are included.
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Mistral’s preview announcement said the model was trained using 3,800 Nvidia Grace Blackwell GPUs in the company’s European data centers.
6 Release reporting describes three reasoning settings—low, medium and high—giving users a choice of reasoning effort.
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Open weights, with a license to read
The weights are available through Hugging Face, and the published license is called the Mistral Ecosystem Open-Weight License. Its text describes it as a modified version of the MIT license.
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32 “Open weights” therefore should not be taken to mean that every kind of redistribution or hosted service is automatically covered by standard MIT terms. Anyone building a commercial offering should review the license itself and confirm which conditions apply to their use.
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The practical significance is that teams can obtain the model weights rather than relying solely on access through a provider’s API. That can make self-hosting or model modification possible, though the release alone does not establish what infrastructure a particular deployment will require.
Cybersecurity claims need careful interpretation
Release coverage reports a 51% score on the Artificial Analysis Cyber Index and a 96.6% average refusal rate for malicious cyber requests.
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33 These are reported evaluation results, not guarantees that the model will refuse every harmful request or that releasing its weights carries no misuse risk.
A defensive-security score and resistance to malicious prompts measure different things. The figures should be considered alongside the evaluation details and the needs of a real deployment; they do not, on their own, settle the risks of a widely available model.
What the release means—and what it does not prove
Large 4 gives organizations another European-developed open-weight option in a market that includes both open and closed models from other regions. Mistral has highlighted the model’s European training infrastructure and its performance against open-weight competitors.
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18 For users, the meaningful distinction is the availability of weights to inspect and deploy—not a general conclusion about model quality based on a company’s country of origin.
The strongest supported takeaway is narrower: Mistral reports meaningful coding benchmark gains between preview and release, and a competitive coding-agent score alongside lower token use in one comparison. Those results may make Large 4 worth testing on a team’s own tasks. They do not establish broad superiority, independently confirm every cybersecurity claim, or remove the need to assess the license and deployment risks.