Thinking Machines Lab co-founder Lilian Weng exits after 20 months and first model launch
快鲤鱼 · wechat · 2026-07-28
OpenAI alum and Thinking Machines Lab co-founder Lilian Weng announced that she is leaving the company, saying her health could no longer sustain the pace and pressure of building the startup. Her departure comes just 20 months after co-founding the company with Mira Murati, and only 12 days after the firm released its first in-house base model, Inkling.
The piece frames Weng’s exit as part of a broader shake-up at the high-profile startup:
- Thinking Machines Lab was founded in February 2025 by former OpenAI CTO Mira Murati and quickly became a capital magnet.
- It raised about $2B in seed funding at a $12B post-money valuation, with investors including a16z, Nvidia, AMD, Accel, and Jane Street.
- Later market chatter put its valuation as high as $50B.
- The company has already seen multiple departures, including co-founders and senior researchers, leaving only two of the original six co-founders.
- Weng’s background is also highlighted: she joined OpenAI in 2018, helped on projects like Dactyl, led safety work, and wrote the widely read technical blog Lil’Log, which helped popularize the classic agent formula: model + memory + planning + tools.
The article argues that the startup’s biggest risk may now be team stability: its pitch depended on elite talent density, but repeated exits are eroding the trust premium attached to that talent.
Related event: Lilian Weng Leaves Thinking Machines Lab Due to Health Issues(16 posts)→
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