China Z.ai Lab Releases GLM-5.2, the Strongest Open-Source Text LLM
Decision Brief
What changedZ.ai Lab open-sourced GLM-5.2, a 753B parameter text-only LLM, on June 16.
Why it mattersGLM-5.2 leads open-source LLMs, offering key resources for AI developers and researchers.
Who should careTeams building on model APIs
Affected stackClaudeOpenAIGLM
Builder actionUpgrade
Source confidenceMedium · Reliable media or first-hand reporting
GLM-5.2, released by China's Z.ai Lab on June 16, 2026 under MIT license, has 753 billion parameters with 40 billion active, supports a 1M token context window, and is text-only. It tops multiple benchmarks, scoring 51 on Intelligence Index v4.1, and ranks second in front-end web development. Available via OpenRouter, it is more cost-effective than GPT-5.5 and Claude Opus. Its SVG animations are impressive but slightly less refined than GLM-5.1.
Summary basis: official / RSS sourceUnless it says 'full article read', this summary is based only on publicly available content — it never pretends to have read restricted originals.
Sources
- Simon Willison：Blog
Hands-on notes on LLM tools, local models, and practical AI engineering.
- Simon Willison：Blog