# Lilian Weng departure and OpenAI return > Live situation record from CLSTR: https://clstr.news/situations/lilian-weng-departure-and-openai-return > Updated: 2026-08-05T11:28:41.000Z. Sources: 10. Developments: 2. In late July 2026, Lilian Weng, a co‑founder of the AI startup Thinking Machines Lab, announced she would leave the company because the sustained stress and workload were harming her health. Her last day was set for July 27, and she soon rejoined OpenAI to lead a team focused on recursive self‑improvement. At the time, Thinking Machines had already seen a wave of founder exits and had recently launched its first open‑weight model, Inkling, followed by the smaller Inkling‑Small. A week later, reports reiterated Weng’s departure as the fourth co‑founder to leave within a year, underscoring the intense competition for top AI talent among firms such as OpenAI, Meta, Anthropic, and Google. Analysts noted that high salaries alone no longer retain researchers, who also seek greater compute resources, project influence, and freedom. The two snapshots together trace the rapid turnover at Thinking Machines Lab and Weng’s move back to OpenAI, highlighting broader talent‑churn dynamics in the AI industry. ## Timeline ### 2026-08-05: Mira Murati's Thinking Machines Lab loses cofounder Lilian Weng Thinking Machines Lab, founded by Mira Murati, lost co‑founder Lilian Weng who returned to OpenAI, highlighting talent churn in the AI sector. 2 sources. https://clstr.news/cluster/mira-muratis-thinking-machines-lab-loses-cofounder-lilian-weng ### 2026-07-29: Lilian Weng Departs Thinking Machines, Returns to OpenAI Over Health Lilian Weng left Thinking Machines Lab citing health concerns and rejoined OpenAI to head a recursive self‑improvement team; Mira Murati voiced support as the startup’s founding team shrinks and it rolls out a 8 sources. https://clstr.news/cluster/lilian-weng-returns-to-openai-after-healthdriven-exit-from-thinking-machines-lab --- Cite as: Lilian Weng departure and OpenAI return. CLSTR, https://clstr.news/situations/lilian-weng-departure-and-openai-return