Magistral Small 2509 is a 24B open-source reasoning model under Apache 2.0 with 70.7% on AIME 2024. It's Mistral AI's compact reasoning option in the Magistral family.
import { streamText } from 'ai'
const result = streamText({ model: 'mistral/magistral-small', prompt: 'Why is the sky blue?'})Magistral Small 2509 was announced alongside Magistral Medium on March 17, 2025 as the open-source counterpart in Mistral AI's first reasoning model release. At 24B parameters, it scores 70.7% on AIME 2024 and 83.3% with majority voting.
Like Magistral Medium, Magistral Small 2509 produces transparent chain-of-thought reasoning and covers the same eight languages: English, French, Spanish, German, Italian, Arabic, Russian, and Simplified Chinese. It applies reasoning depth to business strategy, regulated industries, software engineering, and creative applications, rather than functioning as a smaller instruct model.
The Apache 2.0 license means weights are available on Hugging Face for commercial use.