Leanstral Models by MistralAI

MistralAIApache 2.0Open source

1 model2026

Last refreshed 2026-05-14. Next refresh: weekly.

Details

ResearcherMistralAI

LicenseApache 2.0OSI-approved

Commercial useCommercial use: permitted

Models1

Released2026

Capabilities

JSON / Tool useAll models

Links

Website

About

Mistral's Leanstral family of specialized open-source models focused on formal mathematics, proof engineering, and Lean 4 theorem proving using highly sparse MoE architectures.

Decision facts

Best fit: mathJSON / Tool usemath-heavy prompts
Capability starting point: Leanstral with JSON / Tool use
Lowest tracked input: Not tracked
Closest related family: Ministral

Current Variants

Use-when guidance is based on each model's tracked capabilities, context window, release date, and replacement status.

1 in view

LeanstralCurrent

Use when the workload needs math and JSON / Tool use.

2026-03mathJSON / Tool use

Current Leanstral variants with use-when guidance and lifecycle status
Model	Use when	Released	Signals	Status
Leanstral	Use when the workload needs math and JSON / Tool use.	2026-03	mathJSON / Tool use	Current

Release Timeline

1 release group

2026-03

1 current

Leanstral

mathJSON / Tool use

Current

Specifications(1 models)

Leanstral model specifications comparison
Model	Released	Parameters	JSON / Tool use
Leanstral	2026-03	120B (6B active)	Yes

Models(1)