PatentNext Takeway: Ex parte Desjardins—and especially the USPTO’s decision to make it precedential—appears to be shifting examination away from § 101 and toward § 112 written-description scrutiny, particularly for AI-related inventions. For AI-related inventions, a central takeaway is that practitioners should expect more examiner demands for concrete disclosure of how an AI model is trained, what inputs and outputs are used, how preprocessing and post-processing occur, and how inference or agentic workflows actually operate. Prosecution data and a recent office action example also suggest that written-description rejections are increasing both overall and in AI applications. The practical implication is that patent applicants should not rely on high-level “black box” AI descriptions, but instead should draft specifications with enough technical detail to demonstrate possession of the claimed invention.