A.I. Is Changing How Silicon Valley Builds Start-Ups

Almost every day, Grant Lee, a Silicon Valley entrepreneur, hears from investors who try to persuade him to take their money. Some have even sent him and his co-founders personalized gift baskets.

Mr. Lee, 41, would normally be flattered. In the past, a fast-growing start-up like Gamma, the artificial intelligence start-up he helped establish in 2020, would have constantly looked out for more funding.

But like many young start-ups in Silicon Valley today, Gamma is pursuing a different…