6B Open-Source Leanstral 1.5 Beats GPT-6 Astra on ArXivLean

Mistral's team used the 6B open-source Leanstral 1.5 with light K3 orchestration to beat GPT-6 Astra on ArXivLean with 82.6% pass rate, though each problem consumes up to ten million tokens.

2026-09-11 ~ 2026-09-12 · 4 related posts

• Mistral Prover hits 82.61% verified solutions on MathArena's ArXivLean benchmark — AlbertQJiang · 2026-09-11
• 6B Leanstral 1.5 with light K3 orchestration beats GPT-6 Astra on ArXivLean benchmark — AlbertQJiang · 2026-09-11
• Leanstral 1.5: 6B open model plus K3 orchestration beats GPT-6 Astra on ArXivLean — sophiamyang · 2026-09-11
• Mistral's two-open-model agent hits 82% on ArXivLean using 10M output tokens per problem — scaling01 · 2026-09-12