Mistral released Leanstral-1.5-119B-A6B

Summary

Leanstral 1.5, a free Apache-2.0 licensed model with 6B active parameters, delivers a major performance upgrade in formal verification, saturating miniF2F, solving 587/672 PutnamBench problems, and achieving state-of-the-art results on FATE-H (87%) and FATE-X (34%). Trained through mid-training, supervised fine-tuning, and reinforcement learning with CISPO, it excels in agentic proof engineering and real-world code verification, uncovering 5 previously unknown bugs across 57 repositories tested.

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• Concurrency plus nvfp4 on Blackwell
• 5060 worth it?
• Getting close to 100K context on 32GB VRAM with Qwen3.6-27 at Q8
• I benchmarked 13 models at 65K-128K context to find out what actually matters for agentic workloads
• PSA: Upscaling Gemma 4 requires a proportional layer_scalar adjustment
• Using "applications" to make a smaller model more effective at bigger tasks.