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

Simon Willison · Simon Willison · 2026-06-17

Z.ai releases GLM-5.2, a 753B parameter open-weights text-only LLM under MIT license, which tops the Artificial Analysis Intelligence Index v4.1 and ranks 2nd on the Code Arena WebDev leaderboard despite lacking vision input.

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Chinese AI Models and Products Gain Structural Ground on US Rivals

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Topics: open-weights-llmllm-benchmarksmixture-of-expertsllm-releaseai-china

Claims

GLM-5.2 is a 753B parameter, 1.51TB Mixture of Experts model released under MIT license by Z.ai on June 16, 2026.
GLM-5.2 tops the Artificial Analysis Intelligence Index v4.1 with a score of 51, ahead of MiniMax-M3 (44), DeepSeek V4 Pro (44), and Kimi K2.6 (43).
GLM-5.2 ranks 2nd on the Code Arena WebDev leaderboard behind only Claude Fable 5, despite having no image input capability.
GLM-5.2 uses significantly more output tokens per task (43k) than competing open-weights models such as MiniMax-M3 (24k) and Kimi K2.6 (35k).
GLM-5.2 expands the context window to 1 million tokens, up from GLM-5.1's 200,000 tokens.

Key quotes

GLM-5.2 is the new leading open weights model on the Artificial Analysis Intelligence Index.

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).

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.