Lilian Weng, a co-founder of Thinking Machines, has stepped down from the startup, saying the demands of the role were no longer sustainable for her health. In a message shared internally and later posted publicly, she said the pace and pressure of startup life had become too intense.
Shortly after that announcement, OpenAI confirmed that Weng is returning to the company, where she previously served as vice president of AI Safety Research. In her new role, she will lead a senior team dedicated to advancing internal research and supporting cross-disciplinary work on recursive self-improvement, a concept aimed at helping AI systems refine themselves over time.
The move highlights how quickly top talent continues to circulate across leading AI labs, especially as organizations compete to shape the next phase of intelligent systems. Weng's transition also reflects a broader shift in the industry toward balancing ambitious research goals with sustainable work rhythms.
Thinking Machines co-founder Mira Murati publicly supported Weng's decision to prioritize her well-being, underscoring the human side of innovation in a field defined by speed and scale. As AI research accelerates, leadership choices like this may help define a future where progress and responsibility evolve together.
