“It’s going to be an absolute nightmare,” says an executive at a big American tech company. He is talking about an emerging problem for businesses that use artificial intelligence. AI agents—bots that can read, interpret and act—use masses of processing power and have started to run up huge bills. As they proliferate, the problem will grow. Big companies, the executive points out, typically use hundreds of software programs. If each of those offers agents (as they probably will), AI costs could ...