TL;DR: Mistral Medium 3.5 is a 128B open-weight model released April 29, 2026, with a 256K context window, configurable reasoning, and native multimodal input. It scores 77.6% on SWE-Bench Verified — close but not ahead of Claude Sonnet 4.6 — and ships alongside Vibe, a cloud coding agent that submits pull requests directly to GitHub without you babysitting it. API pricing is $1.50 per million inp
At 3:17 AM on a Tuesday in Q3 2024, our production Kotlin 2.0 microservice fleet hit a 92% memory utilization threshold across 140 nodes, traced to a silent coroutine leak in Ktor 2.2’s request pipeline that had been bleeding 12MB of heap per second for 72 hours. We lost $14k in SLO credits before we found the root cause. A Couple Million Lines of Haskell: Production Engineering at Mercury (78 p