diff --git a/backend/src/main/java/org/raddatz/familienarchiv/controller/DocumentController.java b/backend/src/main/java/org/raddatz/familienarchiv/controller/DocumentController.java
index 92d853c7..0bff2476 100644
--- a/backend/src/main/java/org/raddatz/familienarchiv/controller/DocumentController.java
+++ b/backend/src/main/java/org/raddatz/familienarchiv/controller/DocumentController.java
@@ -12,6 +12,7 @@ import java.util.UUID;
 
 
 import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import org.raddatz.familienarchiv.dto.DocumentSearchResult;
 import org.raddatz.familienarchiv.dto.DocumentUpdateDTO;
 import org.raddatz.familienarchiv.dto.DocumentVersionSummary;
@@ -217,6 +218,7 @@ public class DocumentController {
 
     @PatchMapping("/{id}/training-labels")
     @RequirePermission(Permission.WRITE_ALL)
+    @ApiResponse(responseCode = "204")
     public ResponseEntity<Void> patchTrainingLabel(
             @PathVariable UUID id,
             @RequestBody TrainingLabelRequest req) {
diff --git a/backend/src/test/java/org/raddatz/familienarchiv/controller/DocumentControllerTest.java b/backend/src/test/java/org/raddatz/familienarchiv/controller/DocumentControllerTest.java
index 58cd78a6..3b48e59d 100644
--- a/backend/src/test/java/org/raddatz/familienarchiv/controller/DocumentControllerTest.java
+++ b/backend/src/test/java/org/raddatz/familienarchiv/controller/DocumentControllerTest.java
@@ -32,7 +32,6 @@ import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
-import static org.mockito.ArgumentMatchers.eq;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.multipart;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.patch;