WorkThe story, in brief
Thinking Machines co-founder Lilian Weng left the company citing health reasons, then joined OpenAI
Lilian Weng returns to OpenAI after health-driven exit from Thinking Machines co-founder role
The KeyNews take
Why it matters
Notable personnel move between AI labs signals shifting priorities in AI safety research leadership. Weng's return to OpenAI as a returning executive represents consolidation of talent at the frontier labs.
The key facts
6 to knowLilian Weng left Thinking Machines co-founder role citing health reasons
Weng rejoined OpenAI after departure
Previously served as VP of AI Safety Research at OpenAI
Timeline: July 29, 2026
Weng rejoined OpenAI (previously VP of AI Safety Research there)
Published July 29, 2026
Go to the source
TechCrunch AItechcrunch.com
Publisher excerpt: Weng previously served as the VP of AI Safety Research at OpenAI.