Mistral Large 4 open weights release

Mistral released downloadable weights for Large 4, a mixture-of-experts model with 1.05 trillion total parameters and a 1 million token context window, on Hugging Face. Only about 49 billion parameters are active at any inference step, reducing compute cost for self-hosting. API pricing on Mistral's service dropped to $0.70, $0.07, and $2.10 per million input, cached, and output tokens, from prior prices of $1.36, $0.14, and $4.18. The release uses the Mistral Ecosystem Open-Weight license rather than the Apache 2.0 license that covered Large 3: internal self-hosting is permitted, but selling the model as a service requires a separate commercial license. The model is also available on Open Math OS for approved research teams, a workspace where mathematicians and AI agents collaborate on shared projects built exclusively on open models.

Mistral split the release on safety grounds. Internal testing suggested Large 4 could increase attackers' real-world abilities, even though the model refused 96.6 percent of malicious cyber requests on selected benchmarks. A stronger cyber-specialized variant was withheld from public release and provided only to vetted partners such as Orange Cyberdefense for authorized penetration testing.

Mistral's own benchmark claims show three weeks of reinforcement learning after an earlier preview lifted the Terminal-Bench 4.0 score from 28 to 41 percent, one point above GLM-5.3, and put Large 4 in a tie with GLM-5.3 on Artificial Analysis's Coding Agent Index at roughly 48 percent while consuming 47 percent fewer tokens per task. Third-party evaluators ThibaultJaigu and RequestyAI placed it as the second-best open-source model on their coding benchmark.