She joined Block to build AI. Weeks later, AI cost her job.

Block’s AI-fueled layoffs are a stark reminder of how little protection even the most future-facing roles have in today’s tech economy—and how quickly the ground can shift beneath the people building that future.

On Thursday, Jack Dorsey, CEO and founder of Block—parent company of Square and Cash App—announced plans to cut more than 4,000 jobs, roughly 40% of the workforce, reducing headcount from over 10,000 to just under 6,000 as part of a sweeping restructuring. Dorsey tied the cuts...