Sam Altman has repeatedly suggested that today’s smartphones are not the ideal interface for advanced AI. The ambition is to create what some observers describe as an “AI-native” device—one that could eventually become as important as the smartphone itself.

Apple on Friday accused OpenAI of stealing trade secrets as it seeks to build its own hardware for ChatGPT, a major rupture in a partnership between the iPhone maker and the artificial intelligence company.

Apple said in the lawsuit filed in a California federal court that OpenAI encouraged Apple employees it was recruiting to share confidential information, even guiding how to avoid scrutiny when taking jobs at the other company.

“This case is about Apple’s former employees stealing Apple’s trade secrets for the benefit of OpenAI,” the filing says. “Apple brings this suit to put a stop to it.”