What is GLM-5.2, China's new AI model that has 'shocked' Silicon Valley?

GLM-5.2 is an open-weight AI model developed by China's Zhipu AI for long coding tasks and agentic workflows. The startup claims it matches or outperforms OpenAI's GPT-5.5 and Anthropic's Claude Opus 4.8 models. The model has impressed Silicon Valley developers, with Vercel CEO Guillermo Rauch saying he was "genuinely impressed, almost shocked" by its coding abilities.