Simon Willison Calls Z.ai's GLM-5.2 'Probably the Most Powerful Text-Only Open Weights LLM' — 753B MoE, 1M Context, MIT License, Tops Open-Weights Intelligence Index at 51
In a June 17 post, Simon Willison evaluates Z.ai's newly released GLM-5.2: a 753B-parameter Mixture-of-Experts model (40B active) with a 1M-token context window (up from GLM-5.1's 200K), released under an MIT license at roughly $1.40/$4.40 per million input/output tokens on OpenRouter. Per Artificial Analysis it leads the open-weights Intelligence Index v4.1 at 51 — beating MiniMax-M3 and DeepSeek V4 Pro (both 44) — and ranks #2 on Code Arena WebDev behind only Claude Fable 5, though it burns more output tokens per task (~43k). Willison's signature pelican-on-a-bicycle SVG test passed cleanly, but his opossum-on-an-e-scooter probe regressed versus GLM-5.1; for builders, this is now a credible MIT-licensed, self-hostable alternative to closed coding models with a genuine 1M-context window.
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