Le Chonk goes open: Mistral releases the weights of its 1-trillion-parameter Large 4 ๐
Earlier this month Mistral showed Mistral Large 4, nicknamed "Le Chonk", as a public preview. On 29 October they did the part I was hoping for: they released the weights. Anyone can now download a frontier-class, European-trained model from Hugging Face and run it on their own infrastructure. As someone who loves open models, this one made me smile.
What's inside
According to the model card, Large 4 is a natively multimodal Mixture-of-Experts model with about 1 trillion parameters in total, but only 49 billion active per token (52 billion including embeddings and output layers). It has 128 routed experts, of which 4 are picked per token, plus 1 shared expert that always runs. It reads text and images, writes text, handles a context of 1 million tokens and is natively fluent in more than 160 languages, including every official EU language. So yes, Dutch too.
Mistral says it was trained from scratch on 3,800 NVIDIA Grace Blackwell GPUs in its own datacenters in Europe. You can pick a reasoning effort per request (low, medium or high), and the checkpoint ships with a small built-in draft head for speculative decoding, which Mistral measured at up to 1.9x higher throughput.
Three weeks of extra training
What I find really interesting is how much changed since the preview. Mistral says just three more weeks of reinforcement learning pushed the model forward. On the Artificial Analysis Coding Agent Index it now scores 48%, effectively tied with the leading open model GLM-5.3, while using 47% fewer tokens per task on average. On Terminal-Bench 4.0 it jumped 13 points to 41% and used 30% fewer output tokens.
Security is the other big theme. Mistral reports 51% on the Artificial Analysis Cyber Index, which tests finding, reproducing and patching real vulnerabilities. At the same time, the model refuses malicious cyber requests 96.6% of the time on average, the highest Mistral measured among open models. On the B3 agent security benchmark it resisted 97.1% of attacks, up from 93.3% in the preview.
Why I find this exciting
For me, this is about control. A team can now inspect, fine-tune and host a model of this class themselves, which matters a lot for defenders, banks and public institutions that can't send their data just anywhere. I liked seeing ABN AMRO's director of cyber defense quoted in the announcement, calling open and transparent AI ecosystems essential for innovating responsibly.
The ecosystem was ready on day one too: vLLM, SGLang, transformers and llama.cpp, plus fine-tuning with TRL, Unsloth and Axolotl. Hugging Face even tested a 2-bit quant on a single Apple M3 Ultra and got about 15 tokens per second.
Honest notes
This is not a homelab model for most of us. That 2-bit version still needs a Mac with 512 GB of unified memory, and the full model is meant for multi-GPU servers. The licence is a modified MIT: free to use, modify and commercialize, but companies that offer it as a model-as-a-service need a separate licence. Most benchmark numbers come from Mistral itself, and the full technical report is still "coming soon". Mistral is also open about the risks: it saw potential uplift for real attacks in live traffic and is tightening its guardrails.
Sources
- Mistral Large 4 (Le Chonk) is now open weight (Mistral)
- Mistral Large 4 model card (Hugging Face)
- Welcome Le Chonk: Mistral Large 4 on Hugging Face (Hugging Face blog)
- Mistral releases weights for its trillion-parameter AI model, targeting cybersecurity (TechCrunch)
A trillion parameters, open weights and trained in Europe: I'm curious what the community will build, distill and fine-tune from this one.
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