Thinking Machines co-founder Lilian Weng left the company citing health reasons, then joined OpenAI

# OpenAI Brings Back Safety Expert Lilian Weng, a researcher who previously led AI safety work at OpenAI, has rejoined the company after stepping away from her role at another AI startup called Thinking Machines due to health reasons. Her return is notable because AI safety—making sure powerful AI systems work reliably and don't cause harm—has become increasingly important as companies race to build more advanced AI. Weng's expertise suggests OpenAI is prioritizing the responsible development of its AI technology.