Daniela Amodei, Co-Founder of Anthropic: “When selecting a co-founder, go on a trip together first—shared living is the best litmus test.”

According to Fortune, Daniela Amodei, co-founder and president of Anthropic, shared insights on selecting co-founders during a talk at Stanford Graduate School of Business. She advised entrepreneurs to take a trip with potential co-founders before formalizing the partnership—to assess compatibility in real-life, unfiltered interactions. If both parties feel energized and eager for more after the trip ends, that person is likely an ideal co-founder; if instead they need to “recover from the vacation,” it’s a red flag worth serious consideration. Amodei noted that most of Anthropic’s seven co-founders had worked together for up to 15 years—many previously at OpenAI—where they developed mature feedback mechanisms and shared strong alignment on the company’s vision, forming the core foundation of the team’s success. Paul Graham, co-founder of Y Combinator, likewise observed that in failed startups, founders often overlooked their co-founders’ character and commitment—not their competence. Andy Dunn, co-founder of Bonobos, proposed five concrete evaluation methods: stress testing, time testing, role division, among others. Jeff Rosenthal, co-founder of CIV, recommended that both parties independently draft their visions for the company in writing, then engage in “pen-pal-style” correspondence to ensure strategic alignment and shared expectations.