What is Leanstral?

Leanstral is an open-source AI coding agent introduced by Mistral AI to support the development of formally verified software and mathematical proofs using Lean 4. The model is specifically designed for proof engineering, allowing it to generate code and automatically verify its correctness against formal specifications. Lean 4 is a powerful proof assistant used in advanced mathematics and software verification, and Leanstral is the first AI agent built specifically to operate within this environment. Instead of relying on general-purpose coding models, Leanstral is trained to work directly with formal repositories and structured proof systems. The model uses a sparse architecture with efficient active parameters, enabling it to deliver strong reasoning performance while maintaining computational efficiency. Leanstral can leverage Lean’s verification capabilities to test and validate generated solutions through parallel inference processes. This approach helps ensure that AI-generated code adheres strictly to defined logical and mathematical requirements. The model supports integration with development tools and model communication protocols, enabling it to function within broader AI-assisted coding environments. Benchmarks demonstrate that Leanstral can outperform many large open-source models in proof engineering tasks while operating at a lower cost. Its design allows developers to automatically generate proofs, verify algorithms, and build mathematically sound software implementations. Released under the Apache 2.0 license, Leanstral can be downloaded, fine-tuned, and deployed in private infrastructure. By combining automated coding with formal verification, Leanstral represents a significant step toward building trustworthy AI systems for critical software and research applications.

Pricing

Price Starts At:
Free
Price Overview:
Open source
Free Version:
Free Version available.

Screenshots and Video

Leanstral Screenshot 1

Company Facts

Company Name:
Mistral AI
Date Founded:
2023
Company Location:
France
Company Website:
mistral.ai

Product Details

Deployment
Windows
Mac
Linux
On-Prem
Training Options
Documentation Hub

Product Details

Target Company Sizes
Individual
1-10
11-50
51-200
201-500
501-1000
1001-5000
5001-10000
10001+
Target Organization Types
Mid Size Business
Small Business
Enterprise
Freelance
Nonprofit
Government
Startup
Supported Languages
English

Leanstral Categories and Features