Friday, August 21, 2026 · No. 390Prices synced 3 hours ago
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The AI Model Price Index

leanstral-1-5

by Requesty · listed May 2026T

Leanstral 1.5 is an updated Lean 4 formal proof engineering model from Mistral AI, optimized for automated theorem proving and autoformalization. It has 119B total parameters with 6.5B active and supports a 256K token context window. It supports native function calling and structured output.

Current rates USD per 1M tokens

Inputfree
Outputfree
Cache read—
Cache write—

Against the market

Input price vs. maker flagships ($/1M tokens)
leanstral-1-5leanstral-1-5: free per 1M tokensfreeDeepSeek V4 ProDeepSeek V4 Pro: $0.435 per 1M tokens$0.435Gemini 3.7 FlashGemini 3.7 Flash: $0.75 per 1M tokens$0.75Mistral Medium 3.5Mistral Medium 3.5: $1.50 per 1M tokens$1.50Grok 4.6Grok 4.6: $2.00 per 1M tokens$2.00Qwen3.8 MaxQwen3.8 Max: $2.00 per 1M tokens$2.00Claude Opus 5Claude Opus 5: $5.00 per 1M tokens$5.00GPT-5.6 SolGPT-5.6 Sol: $5.00 per 1M tokens$5.00
Output price vs. maker flagships ($/1M tokens)
leanstral-1-5leanstral-1-5: free per 1M tokensfreeDeepSeek V4 ProDeepSeek V4 Pro: $0.87 per 1M tokens$0.87Gemini 3.7 FlashGemini 3.7 Flash: $3.75 per 1M tokens$3.75Grok 4.6Grok 4.6: $6.00 per 1M tokens$6.00Qwen3.8 MaxQwen3.8 Max: $6.00 per 1M tokens$6.00Mistral Medium 3.5Mistral Medium 3.5: $7.50 per 1M tokens$7.50Claude Opus 5Claude Opus 5: $25.00 per 1M tokens$25.00GPT-5.6 SolGPT-5.6 Sol: $30.00 per 1M tokens$30.00

On the record

Model id
leanstral-1-5
Context window
262K tokens
Max output
33K tokens
Input modalities
text
Output modalities
text
Reasoning
no
Tool calls
yes
Open weights
no
Knowledge cutoff
—
Released
2026-05-27
Last updated
2026-05-27
Provider docs
requesty.ai/solution/llm-routing/models

Back of the envelope

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