Devstral 2

Devstral 2 is Mistral's December 2025 code agents model, built for end-to-end software engineering automation. The 123B-parameter dense transformer scores 72.2% on SWE-bench Verified and is positioned by Mistral as up to 7x more cost-efficient than Claude Sonnet on real-world tasks. The model excels at exploring codebases and orchestrating changes across multiple files, tracking framework dependencies, detecting failures, and retrying with corrections. It handles refactoring, bug fixing, and legacy modernization through natural language while maintaining architectural context. Devstral 2 is released under a modified MIT license and ships with a 256k token context window. It is complemented by Mistral Vibe, an open-source CLI for terminal-based code automation, letting agents and developers explore, modify, and execute changes across entire codebases.