<p>This paper investigates subject-person constraints in Korean with a focus on their interaction with evidential factors. It argues that these constraints only arise in clauses that are large enough to host both Sentience and Evidentiality projections. The analysis posits that the Evidentiality head, carrying a feature that is either co-indexed or contra-indexed with the Sentience argument, restricts subject-person features through the selection of a T head aligned with the features. In the absence of these projections, the constraints do not surface. Person restrictions in Korean are thus analyzed as a Main Clause Phenomenon, confined to assertive structures such as root and semi-root clauses. This account contrasts with Tenny (J East Asian Linguist 15:245–288, 2006) analysis of Japanese, which locates person restrictions in subordinate clauses lacking Sentience projections. The findings underscore the crucial role of clausal architecture in regulating person-feature licensing and evidentiality, and support the presence of covert pragmatic roles in the left periphery, pointing to a tight syntax-pragmatics interface.</p>