Index: iknow-api/Services/Interfaces/IAdminService.cs
===================================================================
--- iknow-api/Services/Interfaces/IAdminService.cs	(revision ea405569ef29f56fbfc4d77708b6b3faf9286097)
+++ iknow-api/Services/Interfaces/IAdminService.cs	(revision ea405569ef29f56fbfc4d77708b6b3faf9286097)
@@ -0,0 +1,28 @@
+using iknow_api.DTOs;
+
+namespace iknow_api.Services
+{
+    public interface IAdminService
+    {
+        // UC012 - subjects
+        Task<List<AdminSubjectDto>> GetSubjectsAsync();
+        Task<AdminResultDto> CreateSubjectAsync(SubjectWriteDto request);
+        Task<AdminResultDto> UpdateSubjectAsync(int subjectId, SubjectWriteDto request);
+        Task<AdminResultDto> DeleteSubjectAsync(int subjectId);
+        Task<AdminResultDto> LinkMajorAsync(int subjectId, MajorLinkDto request);
+        Task<AdminResultDto> UnlinkMajorAsync(int subjectId, int majorId);
+        Task<AdminResultDto> AddPrerequisiteAsync(int subjectId, PrerequisiteDto request);
+        Task<AdminResultDto> RemovePrerequisiteAsync(int subjectId, int dependencyId);
+
+        // UC013 - active semesters
+        Task<List<AdminSemesterDto>> GetSemestersAsync();
+        Task<AdminResultDto> CreateSemesterAsync(SemesterWriteDto request);
+
+        // UC014 - professor assignments
+        Task<ScheduleDto?> GetScheduleAsync(int semesterId);
+        Task<AdminResultDto> AssignAsync(ScheduleWriteDto request);
+        Task<AdminResultDto> UnassignAsync(ScheduleWriteDto request);
+
+        Task<List<SubjectRefDto>> GetMajorsAsync();
+    }
+}