According to tech analyst Simon Willison, Chinese AI lab Z.ai has released GLM-5.2, a massive open-weights language model now ranked the most powerful text-only LLM in the world. The 753-billion-parameter model, released under an MIT license on June 16th, topped Artificial Analysis's latest benchmark rankings and placed second on the Code Arena's front-end development leaderboard, behind only Claude Fable 5. With a million-token context window and aggressive pricing—$1.40 per million input tokens compared to $5 for GPT-5.5—the model represents a significant shift in how frontier AI capability is being distributed. The main trade-off: it consumes more output tokens per task than competitors, but its performance suggests that openness and capability are no longer mutually exclusive.

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