diff --git a/backend/src/main/java/org/raddatz/familienarchiv/service/CommentService.java b/backend/src/main/java/org/raddatz/familienarchiv/service/CommentService.java
index 554fa492..da34588f 100644
--- a/backend/src/main/java/org/raddatz/familienarchiv/service/CommentService.java
+++ b/backend/src/main/java/org/raddatz/familienarchiv/service/CommentService.java
@@ -13,6 +13,8 @@ import org.raddatz.familienarchiv.repository.CommentRepository;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
+import java.util.Collection;
+import java.util.HashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
@@ -29,6 +31,15 @@ public class CommentService {
     private final AuditService auditService;
     private final TranscriptionService transcriptionService;
 
+    public Map<UUID, UUID> findAnnotationIdsByIds(Collection<UUID> commentIds) {
+        if (commentIds == null || commentIds.isEmpty()) return Map.of();
+        Map<UUID, UUID> result = new HashMap<>();
+        for (DocumentComment c : commentRepository.findAllById(commentIds)) {
+            if (c.getAnnotationId() != null) result.put(c.getId(), c.getAnnotationId());
+        }
+        return result;
+    }
+
     public List<DocumentComment> getCommentsForBlock(UUID blockId) {
         List<DocumentComment> roots = commentRepository.findByBlockIdAndParentIdIsNull(blockId);
         return withRepliesAndMentions(roots);
diff --git a/backend/src/test/java/org/raddatz/familienarchiv/service/CommentServiceTest.java b/backend/src/test/java/org/raddatz/familienarchiv/service/CommentServiceTest.java
index 19eb0b8d..a7854424 100644
--- a/backend/src/test/java/org/raddatz/familienarchiv/service/CommentServiceTest.java
+++ b/backend/src/test/java/org/raddatz/familienarchiv/service/CommentServiceTest.java
@@ -641,6 +641,64 @@ class CommentServiceTest {
         verify(auditService, never()).logAfterCommit(eq(AuditKind.MENTION_CREATED), any(), any(), any());
     }
 
+    // ─── findAnnotationIdsByIds ───────────────────────────────────────────────
+
+    @Test
+    void findAnnotationIdsByIds_returnsMap_forKnownIds() {
+        UUID commentA = UUID.randomUUID();
+        UUID annotationA = UUID.randomUUID();
+        UUID commentB = UUID.randomUUID();
+        UUID annotationB = UUID.randomUUID();
+        when(commentRepository.findAllById(List.of(commentA, commentB)))
+                .thenReturn(List.of(
+                        DocumentComment.builder().id(commentA).annotationId(annotationA).build(),
+                        DocumentComment.builder().id(commentB).annotationId(annotationB).build()
+                ));
+
+        assertThat(commentService.findAnnotationIdsByIds(List.of(commentA, commentB)))
+                .containsOnly(
+                        java.util.Map.entry(commentA, annotationA),
+                        java.util.Map.entry(commentB, annotationB)
+                );
+    }
+
+    @Test
+    void findAnnotationIdsByIds_returnsEmptyMap_forEmptyInput() {
+        assertThat(commentService.findAnnotationIdsByIds(List.of())).isEmpty();
+        verify(commentRepository, never()).findAllById(anyList());
+    }
+
+    @Test
+    void findAnnotationIdsByIds_omitsUnknownIds() {
+        UUID known = UUID.randomUUID();
+        UUID knownAnnotation = UUID.randomUUID();
+        UUID missing = UUID.randomUUID();
+        when(commentRepository.findAllById(List.of(known, missing)))
+                .thenReturn(List.of(
+                        DocumentComment.builder().id(known).annotationId(knownAnnotation).build()
+                ));
+
+        assertThat(commentService.findAnnotationIdsByIds(List.of(known, missing)))
+                .containsOnly(java.util.Map.entry(known, knownAnnotation))
+                .doesNotContainKey(missing);
+    }
+
+    @Test
+    void findAnnotationIdsByIds_omitsCommentsWithNullAnnotationId() {
+        UUID legacy = UUID.randomUUID();
+        UUID block = UUID.randomUUID();
+        UUID annotation = UUID.randomUUID();
+        when(commentRepository.findAllById(List.of(legacy, block)))
+                .thenReturn(List.of(
+                        DocumentComment.builder().id(legacy).annotationId(null).build(),
+                        DocumentComment.builder().id(block).annotationId(annotation).build()
+                ));
+
+        assertThat(commentService.findAnnotationIdsByIds(List.of(legacy, block)))
+                .containsOnly(java.util.Map.entry(block, annotation))
+                .doesNotContainKey(legacy);
+    }
+
     private void stubBlock(UUID docId, UUID blockId) {
         when(transcriptionService.getBlock(docId, blockId))
                 .thenReturn(TranscriptionBlock.builder()