Mistral AI releases Leanstral-2603, an open-source Lean 4 proof agent
AIMistral AI released Leanstral 119B A6B on Hugging Face as an open-source code agent for Lean 4 proof engineering. The model uses 128 experts with 4 active per token, 6.5B activated parameters, a 256k token context window, and accepts text and image input under the Apache 2.0 license. The page also documents vLLM server deployment and Mistral Vibe integration.
Why it matters: The source specifies Leanstral's 119B MoE architecture, 256k context, Apache 2.0 license, and vLLM setup, showing how the Lean 4 proof agent could be deployed locally.