Lilian Weng Returns to OpenAI After Thinking Machines Exit

In a swift career reversal, prominent AI researcher Lilian Weng announced her departure from the AI startup Thinking Machines Lab on July 29, only to be confirmed as rejoining OpenAI the following day. Weng, a co-founder of Thinking Machines, cited debilitating health issues stemming from startup pressures as her reason for leaving, before accepting a senior research leadership role at her former employer.

Weng publicly announced her resignation on July 29, describing an intense and unsustainable workload. In a message shared internally and on social media, she stated that the consistent stress and workload had pushed her beyond what her health could sustain physically. She noted she had been ill more often in the past seven months than at any point in her life. Weng expressed feeling terrible about disappointing her team but emphasized the need to prioritize her health, seeking a role with defined responsibilities in a more predictable environment.

Her departure was met with public support from Thinking Machines CEO and co-founder Mira Murati, a former OpenAI chief technology officer, who wrote that the team would miss Weng and was glad she was putting her health first.