Mistral releases the open weights of an improved Mistral Large 4

On 29 October 2026 Mistral released the weights of Mistral Large 4, nicknamed Le Chonk, its flagship natively multimodal model with 1 trillion parameters. The model entered public preview earlier in October; Mistral says three further weeks of reinforcement learning since then improved coding and defensive cybersecurity and made reasoning more efficient, which lowers inference costs. It now offers three reasoning modes so developers can trade performance against cost.

Mistral's own figures put it first among open-weight models on Cognition's FrontierCode 2.0 (19.7%) and Terminal-Bench 4.0 (41%, up 13 points from the preview). On the Artificial Analysis Coding Agent Index it scores 48%, roughly level with GLM-5.3 while using 47% fewer tokens per task, and it scores 51% on the Artificial Analysis Cyber Index.

Mistral says the model refuses 96.6% of malicious cyber requests on average, and that it saw potential uplift for real attacks in live traffic during the preview, so it is tightening its guardrails. A specialised cybersecurity variant is in preview for vetted enterprise partners such as Orange Cyberdefense. The company presents the model, trained from scratch in Europe, as a base for self-hosted, customised deployments.