Proprietary coding agents are powerful, but every token you send to a cloud API is a token that leaves your codebase. Devstral 2, released December 9, 2025 by Mistral AI, changes that calculus. At 72.2% on SWE-bench Verified — the industry-standard benchmark for real GitHub issue resolution — it matches Claude Sonnet 4.5's general performance territory while running fully on-premise on a single RTX 4090 or a Mac with 32GB RAM. This guide covers what Devstral 2 and Devstral Small 2 are, their specs and benchmarks, how to pull and run the smaller variant via Ollama, and how to wire either model into your daily coding workflow. Effloow Lab verified Ollama compatibility (v0.20.5), confirmed registry tags, and documented hardware requirements before writing this guide. See data/lab-runs/devstral-2-mistral-coding-agent-local-guide-2026.md for the full evidence record.…