GLM-5.2 is probably the most powerful text-only open weights LLM

Simon Willison's AI Notes 发布的媒体报道：Chinese AI lab Z.ai released GLM-5.2 to their coding plan subscribers on June 13th, and then yesterday (June 16th) released the full open weights under an MIT license. Similar in size to their previous GLM-5 and GLM-5.1 releases this is a 753B parameter, 1.51TB monster - with 40 active parameters (Mixture of Experts). GLM-5.2 is a text input only model - Z.ai have a separate vision family most recently represented by GLM-5V-Turbo , but that one isn't open weights. GLM-5.2 has a 1 million token context window, up from GLM-5.1's 200,000. The buzz around this model is strong. Artificial Analysis, who run one of the most widely respected independent benchmarks: GLM-5.2 is the new leading open weights model on the Artificial Analysis Intelligence Index . GLM-5.2 is the leading open weights model on the Intelligence Index v4.1. At 51, it leads MiniMax-M3 (44), DeepSeek V4 Pro (max, 44) and Kimi K2.6 (43) They did however find it to be quite token-hungry: GLM-5.2 uses more output tokens per task than other leading open weights models: the model uses 43k output tokens per Intelligence Index task, up from GLM-5.1 (26k) and above MiniMax-M3 (24k), Kimi K2.6 (35k) and DeepSeek V4 Pro (max, 37k) The model is also now ranked 2nd on the Code Arena WebDev leaderboard , behind only Claude Fable 5. That leaderboard measures "front-end web development tasks, including agentic coding workflows". I'm impressed to see it rank so highly given the lack of image input, which I had incorrectly assumed was a key part of building a truly great frontend coding model. I've been trying it out via OpenRouter , which has it from 9 different providers, almost all of which are charging $1.40/million for input and $4.40/million for output. For comparison, GPT-5.5 is $5/$30 and Claude Opus 4.5-4.8 is $5/$25. Excellent pelican, disappointing opossum GLM-5.1 gave me one of my favorite pelicans and my all time favorite opossum (for the prompt "Generate an SVG of a NORTH VIRGINIA OPOSSUM ON AN E-SCOOTER".) Interestingly, in both of those cases the model chose to return SVG wrapped in an HTML document that added additional animations using CSS. Let's try GLM-5.2. For "Generate an SVG of a pelican riding a bicycle" I got this : It's a self-contained fully animated SVG, and the animations aren't broken! Often I'll see eyes falling off or wheels rotating independently of the bicycle but here everything works great. It's a very nice vector illustration of a pelican too. Very impressive. Sadly, the NORTH VIRGINIA OPOSSUM ON AN E-SCOOTER did not come out nearly as well : This is such a step down from GLM-5.1! As a reminder, that possum looked like this: 5.2 didn't even try to animate it. Tags: ai , generative-ai , llms , pelican-riding-a-bicycle , llm-release , openrouter , ai-in-china , glm