The patent system grants inventors temporary monopoly rights in exchange for a public disclosure detailing their innovation. These disclosures are meant to allow others to recreate and build on the patented innovation. We examine how the quality of these disclosures affects follow-on innovation. We use the plausibly exogenous assignment to patent applications of patent examiners who differ in their enforcement of disclosure requirements as a source of variation in disclosure quality. We find that some examiners are significantly more lenient with respect to patent disclosure quality requirements, and that patents granted by these examiners include significantly lower-quality disclosures. These patents generate significantly less follow-on innovation.