Devstral: Fine-tuning Language Models for Coding Agent Applications
Software Engineering
2025-10-01 v1 Artificial Intelligence
Abstract
We introduce Devstral-Small, a lightweight open source model for code agents with the best performance among models below 100B size. In this technical report, we give an overview of how we design and develop a model and craft specializations in agentic software development. The resulting model, Devstral-Small is a small 24B model, fast and easy to serve. Despite its size, Devstral-Small still attains competitive performance compared to models more than an order of magnitude larger.
Keywords
Cite
@article{arxiv.2509.25193,
title = {Devstral: Fine-tuning Language Models for Coding Agent Applications},
author = {Abhinav Rastogi and Adam Yang and Albert Q. Jiang and Alexander H. Liu and Alexandre Sablayrolles and Amélie Héliou and Amélie Martin and Anmol Agarwal and Andy Ehrenberg and Andy Lo and Antoine Roux and Arthur Darcet and Arthur Mensch and Baptiste Bout and Baptiste Rozière and Baudouin De Monicault and Chris Bamford and Christian Wallenwein and Christophe Renaudin and Clémence Lanfranchi and Clément Denoix and Corentin Barreau and Darius Dabert Devon Mizelle and Diego de las Casas and Elliot Chane-Sane and Emilien Fugier and Emma Bou Hanna and Gabrielle Berrada and Gauthier Delerce and Gauthier Guinet and Georgii Novikov and Graham Neubig and Guillaume Lample and Guillaume Martin and Himanshu Jaju and Jan Ludziejewski and Jason Rute and Jean-Malo Delignon and JeanHadrien Chabran and Joachim Studnia and Joep Barmentlo and Jonas Amar and Josselin Somerville Roberts and Julien Denize and Karan Saxena and Karmesh Yadav and Kartik Khandelwal and Khyathi Raghavi Chandu and Kush Jain and Lélio Renard Lavaud and Léonard Blier and Lingxiao Zhao and Louis Martin and Lucile Saulnier and Luyu Gao and Marie Pellat and Mathilde Guillaumin and Mathis Felardos and Matthieu Dinot and Maxime Darrin and Maximilian Augustin and Mickaël Seznec and Neha Gupta and Nikhil Raghuraman and Olivier Duchenne and Patricia Wang and Patrick von Platen and Patryk Saffer and Paul Jacob and Paul Wambergue and Paula Kurylowicz and Philomène Chagniot and Pierre Stock and Pravesh Agrawal and Rémi Delacourt and Roman Soletskyi and Romain Sauvestre and Sagar Vaze and Sanchit Gandhi and Sandeep Subramanian and Shashwat Dalal and Siddharth Gandhi and Soham Ghosh and Srijan Mishra and Sumukh Aithal and Szymon Antoniak and Teven Le Scao and Thibaut Lavril and Thibault Schueller and Thomas Foubert and Thomas Robert and Thomas Wang and Timothée Lacroix and Tom Bewley and Valeriia Nemychnikova and Victor Paltz and Virgile Richard and Wen-Ding Li and William Marshall and Xingyao Wang and Xuanyu Zhang and Yihan Wan and Yunhao Tang},
journal= {arXiv preprint arXiv:2509.25193},
year = {2025}
}