diff --git a/backend/src/main/java/org/raddatz/familienarchiv/document/DocumentService.java b/backend/src/main/java/org/raddatz/familienarchiv/document/DocumentService.java
index 66a56a22..d4715f40 100644
--- a/backend/src/main/java/org/raddatz/familienarchiv/document/DocumentService.java
+++ b/backend/src/main/java/org/raddatz/familienarchiv/document/DocumentService.java
@@ -1008,9 +1008,20 @@ public class DocumentService {
 
     /**
      * Lightweight summary lookup for internal use (e.g. journey item append validation).
-     * Intentionally skips scope checks and tag-colour resolution — safe only
-     * under the current single-tenant model where all authenticated users share
-     * the same document scope. Called within a caller-provided transaction.
+     *
+     * <p><strong>Security contract — read before calling:</strong>
+     * <ol>
+     *   <li>This method intentionally bypasses per-document scope checks and
+     *       tag-colour resolution. It must only be invoked after
+     *       {@code @RequirePermission(BLOG_WRITE)} has already been enforced at
+     *       the controller layer, guaranteeing the caller is an authenticated
+     *       author.</li>
+     *   <li>In {@code JourneyItemService.append()}, it is additionally guarded by the
+     *       JOURNEY-type check that fires before this call — so the method is never
+     *       reached for STORY-type Geschichten.</li>
+     * </ol>
+     * Under the current single-tenant model every authenticated author shares the
+     * same document scope, so skipping per-document scope checks is safe.
      */
     public Document findSummaryByIdInternal(UUID id) {
         return documentRepository.findById(id)
diff --git a/backend/src/test/java/org/raddatz/familienarchiv/geschichte/journeyitem/JourneyItemServiceTest.java b/backend/src/test/java/org/raddatz/familienarchiv/geschichte/journeyitem/JourneyItemServiceTest.java
index 91a51c93..c411a3bb 100644
--- a/backend/src/test/java/org/raddatz/familienarchiv/geschichte/journeyitem/JourneyItemServiceTest.java
+++ b/backend/src/test/java/org/raddatz/familienarchiv/geschichte/journeyitem/JourneyItemServiceTest.java
@@ -39,6 +39,7 @@ import static org.mockito.ArgumentMatchers.isNull;
 import static org.mockito.Mockito.lenient;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.when;
 
 @ExtendWith(MockitoExtension.class)
@@ -235,6 +236,26 @@ class JourneyItemServiceTest {
                         .isEqualTo(ErrorCode.GESCHICHTE_TYPE_MISMATCH));
     }
 
+    @Test
+    void append_never_calls_findSummaryByIdInternal_when_geschichte_type_is_STORY() {
+        // Arrange: mock geschichteQueryService.findById() to return a STORY-type Geschichte
+        UUID storyId = UUID.randomUUID();
+        Geschichte story = Geschichte.builder()
+                .id(storyId)
+                .type(GeschichteType.STORY)
+                .build();
+        when(geschichteQueryService.findById(storyId)).thenReturn(Optional.of(story));
+
+        // Act + Assert: calling append throws GESCHICHTE_TYPE_MISMATCH
+        JourneyItemCreateDTO dto = new JourneyItemCreateDTO();
+        dto.setDocumentId(UUID.randomUUID());
+        assertThatThrownBy(() -> journeyItemService.append(storyId, dto))
+                .isInstanceOf(DomainException.class);
+
+        // Verify: document service was never touched — type guard fired first
+        verifyNoInteractions(documentService);
+    }
+
     @Test
     void append_returns404_when_documentId_does_not_exist() {
         Geschichte journey = journey(geschichteId);