Corrected: Leanstral 1.5: Proof Abundance for All

MistralNew modelConfirmed

Correction: Leanstral 1.5 helps researchers and developers check mathematical proofs and software claims using Lean 4, a tool that verifies them.

Mistral releases Leanstral 1.5, a specialist model that helps researchers and developers check mathematical proofs and software properties using Lean 4, a tool for verifying such claims.

Who can use it: Apache 2.0 weights are available to download. The hosted API requires an API key and uses the model name leanstral-1-5.
When: The July 2 announcement says the weights and free API endpoint are available. An exact release time is not specified by the source.

Mistral AI official announcement Announced 2026-07-02 · date only

Read the official announcement for access details. Availability can depend on your plan, region or workplace settings.

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