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MistralTextCommonRetired

Leanstral 1.5

An updated Lean 4 formal proof engineering model optimised for automated theorem proving and autoformalization. 119B total parameters, 6.5B active.

labs-leanstral-1-5-1
Type
Text
Quality
Not rated yet
Context window
262,144 tokens
Max output
128,000 tokens
Input price
Free
Output price
Free
Cache read
—
Cache write
—
Released
Jun 30, 2026
Knowledge cutoff
—
Takes in
Text, Image
Puts out
Text
Reasoning
Yes
Tool calling
Yes
Structured output
Yes
File attachments
Yes
Access
Free
License
Apache 2.0
Rarity
Common
Set number
936/1044
Open Mistral docsWhere to run it 2Meet its creatureBattle Nemotron 3.5 Super VL 120B A12B

No matching Hugging Face repo was found, so this shows Mistral’s usual open-weight license. Check the model card before relying on it. Specs from models.dev, last changed Oct 19, 2026. Official source: docs.mistral.ai.

How good is it?

Public leaderboard scores for Leanstral 1.5, refreshed daily from Epoch AI and LMArena.

No public leaderboard lists Leanstral 1.5 yet. Epoch AI and LMArena cover most chat, image, and video models from the big labs; embeddings, speech, and small open models mostly go unrated.

Where to run it

2 providers sell Leanstral 1.5 through an API. Prices are per million tokens, cheapest first.

API providers

ProviderInputOutputContext
MistralOfficialFreelabs-leanstral-1-5-1FreeFree262K
RequestyFreeleanstral-1-5FreeFree262K

From models.dev and Hugging Face, checked daily. Resellers’ listings can lag behind their price pages, so confirm with the provider before you commit.

Face off

Current text models from other labs at a similar output price.

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