# GLM-5.2 is probably the most powerful text-only open weights LLM > Source: > Published: 2026-06-17 23:58:39+00:00 Chinese AI lab [Z.ai](https://z.ai/) released GLM-5.2 [to their coding plan subscribers](https://x.com/Zai_org/status/2065704919299235870) 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 753B parameter, [1.51TB](https://huggingface.co/zai-org/GLM-5.2) 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](https://x.com/Zai_org/status/2039371126984360085), 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](https://artificialanalysis.ai/articles/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](https://arena.ai/leaderboard/code/webdev), 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](https://openrouter.ai/z-ai/glm-5.2), 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. GLM-5.1 gave me [one of my favorite pelicans](https://simonwillison.net/2026/Apr/7/glm-51/) and my [all time favorite opossum](https://simonwillison.net/2026/Apr/7/glm-51/#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](https://gist.github.com/simonw/5c989366b796f054d9ae1ad7e38dc03a): 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](https://gist.github.com/simonw/5913b56e3d0ba9a2ece75ce1471f87bb): 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](https://simonwillison.net/tags/ai), [generative-ai](https://simonwillison.net/tags/generative-ai), [llms](https://simonwillison.net/tags/llms), [pelican-riding-a-bicycle](https://simonwillison.net/tags/pelican-riding-a-bicycle), [llm-release](https://simonwillison.net/tags/llm-release), [openrouter](https://simonwillison.net/tags/openrouter), [ai-in-china](https://simonwillison.net/tags/ai-in-china), [glm](https://simonwillison.net/tags/glm)