Z.ai drops open-source GLM-5.1 coding agent
Z.ai just released GLM-5.1, an open-source flagship coding model licensed under MIT that scored 58.4 on SWE-Bench Pro, edging out GPT-5.4 and Claude Opus 4.6. Designed for complex long-horizon tasks, it maintains steady performance gains over hundreds of iterations and thousands of tool calls. Open-source agentic coding is officially competing at the very frontier.