
He helped build GPT-3, then helped found Anthropic. His current workshop tests what Claude can do - and what happens when a promising demonstration meets ordinary people.

He left a comfortable engineering career, changed course after one unsettling book, and helped build both GPT-3 and Anthropic. Now Ben Mann works where product ambition and AI caution keep sharing the same desk.

He spent eight years learning how to build startups, then chose to become a novice again. A decade later, the former group-dating founder is responsible for the machinery beneath Claude.
The AI that read your customer feedback so you didn't have to - one of the first companies to turn GPT-3 into a working analyst.
Justin Fineberg is the co-founder and CEO of Cassidy, a New York-based platform that lets non-technical teams build AI agents and automations powered by their own company data. He got early beta access to OpenAI's GPT-3 in 2020, left a product role at Blade in 2022, and teamed up with engineer Ian Woodfill to launch Cassidy. Alongside building the company, he grew an audience of more than 400,000 followers across TikTok, Instagram, X and YouTube by explaining how AI reshapes business. Cassidy raised a $10M Series A led by HOF Capital in 2025, bringing total funding to roughly $13.7M.