Devstral Medium

Devstral Medium is a coding-centric language model released by Mistral AI in July 2025. Developed in partnership with All Hands AI, the model is part of the Devstral series designed specifically for agentic software engineering tasks. It is positioned as a high-capacity model optimized for complex reasoning, tool use, and codebase exploration.

The model demonstrates high performance on software engineering benchmarks, notably achieving a 61.6% score on SWE-Bench Verified. This evaluation measures a model's ability to resolve real-world issues from GitHub repositories by generating functional patches. Devstral Medium is designed to function as the core engine for autonomous coding agents, supporting structured outputs and native function calling to facilitate interaction with development environments.

Unlike the smaller open-weight variants in the Devstral family, Devstral Medium is a proprietary model accessible via API. It features a context window of 131,072 tokens and utilizes Mistral's Tekken tokenizer for improved processing efficiency of code and technical text across multiple programming languages.