diff --git a/shared/schema.ts b/shared/schema.ts
index 2181b63..a63b5c7 100644
--- a/shared/schema.ts
+++ b/shared/schema.ts
@@ -257,10 +257,14 @@ export const shiftAssignments = pgTable("shift_assignments", {
   shiftId: varchar("shift_id").notNull().references(() => shifts.id, { onDelete: "cascade" }),
   guardId: varchar("guard_id").notNull().references(() => guards.id, { onDelete: "cascade" }),
   
+  // Planned shift times (when the guard is scheduled to work)
+  plannedStartTime: timestamp("planned_start_time").notNull(),
+  plannedEndTime: timestamp("planned_end_time").notNull(),
+  
   assignedAt: timestamp("assigned_at").defaultNow(),
   confirmedAt: timestamp("confirmed_at"),
   
-  // Actual check-in/out times
+  // Actual check-in/out times (recorded when guard clocks in/out)
   checkInTime: timestamp("check_in_time"),
   checkOutTime: timestamp("check_out_time"),
 });
@@ -700,10 +704,25 @@ export const insertShiftFormSchema = z.object({
   status: z.enum(["planned", "active", "completed", "cancelled"]).default("planned"),
 });
 
-export const insertShiftAssignmentSchema = createInsertSchema(shiftAssignments).omit({
-  id: true,
-  assignedAt: true,
-});
+export const insertShiftAssignmentSchema = createInsertSchema(shiftAssignments)
+  .omit({
+    id: true,
+    assignedAt: true,
+  })
+  .extend({
+    plannedStartTime: z.union([z.string(), z.date()], {
+      required_error: "Orario inizio richiesto",
+      invalid_type_error: "Orario inizio non valido",
+    }).transform((val) => new Date(val)),
+    plannedEndTime: z.union([z.string(), z.date()], {
+      required_error: "Orario fine richiesto",
+      invalid_type_error: "Orario fine non valido",
+    }).transform((val) => new Date(val)),
+  })
+  .refine((data) => data.plannedEndTime > data.plannedStartTime, {
+    message: "L'orario di fine deve essere successivo all'orario di inizio",
+    path: ["plannedEndTime"],
+  });
 
 export const insertCcnlSettingSchema = createInsertSchema(ccnlSettings).omit({
   id: true,