Mistral previews Large 4, a 1 trillion parameter open-weight model

Mistral AI opened a public preview of Mistral Large 4 on the 6th of October 2026, the company said. Mistral said it is its largest model so far, with 1 trillion parameters.

The company said it will release the model files for anyone to download by the end of October.

Why it matters

Mistral says the model can help defend software. It solved 93 percent of the 40 Cybench challenges, a set of security exercises, the company said.

On a test that asks a model to recreate a real software flaw and then fix it, it scored 82 percent, Mistral said. Some closed models score near zero there, because they refuse the task, Mistral said.

Key facts

Developers can try the preview in Mistral Studio for 1.36 dollars per million input tokens, the company said. Tokens are small pieces of text.

Only 52 billion of its parameters work at a time, the announcement says.

In a blind test with Surge AI, experts rated coding answers from one to five, Mistral said. The preview scored 3.74, second of five, behind Anthropic's Claude Opus 5 at 4.22.

Mistral trained the model on 3,800 NVIDIA chips in its own datacenters in Europe, the company said. Its training data covered more than 160 languages.

What's next

Mistral said it will publish more details and test results when it releases the files. Until then, security experts, partners and governments are testing it, the company said.

The announcement does not name the licence.