formal-verification
2 articles tagged with formal-verification
May 28, 2026
model releaseMistral AI
Mistral releases Leanstral, 6B-parameter open-source model for Lean 4 formal proof verification
Mistral AI released Leanstral, the first open-source code agent designed specifically for Lean 4 formal proof verification. The model uses 6B active parameters in a sparse 120B architecture and is available under Apache 2.0 license with free API access.
March 17, 2026
analysis
Mistral's Leanstral code verification agent outperforms Claude Sonnet at 15% of the cost
Mistral has released Leanstral, a 120B-parameter code verification agent built with the Lean programming language, claiming it outperforms larger open-source models and offers significant cost advantages over Anthropic's Claude suite. The model achieves a pass@2 score of 26.3—beating Claude Sonnet by 2.6 points—while costing $36 to run compared to Sonnet's $549.