diff --git a/src/basic_memory/sync/sync_service.py b/src/basic_memory/sync/sync_service.py
index 945add2a..c86149de 100644
--- a/src/basic_memory/sync/sync_service.py
+++ b/src/basic_memory/sync/sync_service.py
@@ -1087,6 +1087,22 @@ class SyncService:
         initial_markdown_content = initial_markdown_bytes.decode("utf-8")
         file_metadata = await self.file_service.get_file_metadata(path)
         initial_checksum = await compute_checksum(initial_markdown_bytes)
+        existing_entity = await self.entity_repository.get_by_file_path(path)
+        if existing_entity is not None and existing_entity.checksum == initial_checksum:
+            logger.debug(
+                f"Markdown sync skipped unchanged file: path={path}, "
+                f"entity_id={existing_entity.id}, checksum={initial_checksum[:8]}"
+            )
+            return SyncedMarkdownFile(
+                entity=existing_entity,
+                checksum=initial_checksum,
+                markdown_content=initial_markdown_content,
+                file_path=path,
+                content_type=self.file_service.content_type(path),
+                updated_at=file_metadata.modified_at,
+                size=file_metadata.size,
+            )
+
         indexed = await self.batch_indexer.index_markdown_file(
             IndexInputFile(
                 path=path,
diff --git a/tests/sync/test_sync_one_markdown_file.py b/tests/sync/test_sync_one_markdown_file.py
index b423f2bc..8df36544 100644
--- a/tests/sync/test_sync_one_markdown_file.py
+++ b/tests/sync/test_sync_one_markdown_file.py
@@ -194,6 +194,103 @@ async def test_sync_one_markdown_file_does_not_reread_for_initial_checksum_when_
     assert result.checksum == await compute_checksum(file_path.read_bytes())
 
 
+@pytest.mark.asyncio
+async def test_sync_one_markdown_file_skips_indexing_when_checksum_matches(
+    sync_service,
+    test_project,
+    monkeypatch,
+):
+    """A matching DB checksum is the consistency boundary for derived indexes."""
+    original_content = dedent(
+        f"""\
+        ---
+        title: Already Current
+        type: note
+        permalink: {test_project.name}/notes/already-current
+        ---
+
+        # Already Current
+
+        - [note] Derived indexes are assumed current when the file checksum matches.
+        """
+    )
+    file_path = _write_markdown(
+        Path(test_project.path),
+        "notes/already-current.md",
+        original_content,
+    )
+
+    initial = await sync_service.sync_one_markdown_file(
+        "notes/already-current.md",
+        index_search=False,
+    )
+    assert initial.checksum == await compute_checksum(file_path.read_bytes())
+
+    index_markdown_file = AsyncMock(side_effect=AssertionError("indexer should not run"))
+    index_entity_data = AsyncMock(side_effect=AssertionError("search should not refresh"))
+    monkeypatch.setattr(sync_service.batch_indexer, "index_markdown_file", index_markdown_file)
+    monkeypatch.setattr(sync_service.search_service, "index_entity_data", index_entity_data)
+
+    result = await sync_service.sync_one_markdown_file("notes/already-current.md")
+
+    index_markdown_file.assert_not_awaited()
+    index_entity_data.assert_not_awaited()
+    assert result.entity.id == initial.entity.id
+    assert len(result.entity.observations) == 1
+    assert result.markdown_content == file_path.read_bytes().decode("utf-8")
+    assert result.checksum == initial.checksum
+
+
+@pytest.mark.asyncio
+async def test_sync_one_markdown_file_indexes_when_checksum_differs(
+    sync_service,
+    test_project,
+    monkeypatch,
+):
+    """A DB checksum mismatch still takes the full indexing path."""
+    initial_content = dedent(
+        f"""\
+        ---
+        title: Changed
+        type: note
+        permalink: {test_project.name}/notes/changed
+        ---
+
+        # Changed
+
+        Original body.
+        """
+    )
+    file_path = _write_markdown(
+        Path(test_project.path),
+        "notes/changed.md",
+        initial_content,
+    )
+    initial = await sync_service.sync_one_markdown_file("notes/changed.md", index_search=False)
+
+    updated_content = initial_content.replace("Original body.", "Updated body.")
+    file_path.write_text(updated_content, encoding="utf-8")
+
+    original_index_markdown_file = sync_service.batch_indexer.index_markdown_file
+
+    async def index_markdown_file_spy(*args, **kwargs):
+        return await original_index_markdown_file(*args, **kwargs)
+
+    index_markdown_file = AsyncMock(side_effect=index_markdown_file_spy)
+    index_entity_data = AsyncMock()
+    monkeypatch.setattr(sync_service.batch_indexer, "index_markdown_file", index_markdown_file)
+    monkeypatch.setattr(sync_service.search_service, "index_entity_data", index_entity_data)
+
+    result = await sync_service.sync_one_markdown_file("notes/changed.md")
+
+    index_markdown_file.assert_awaited_once()
+    index_entity_data.assert_awaited_once()
+    assert result.entity.id == initial.entity.id
+    assert result.markdown_content == file_path.read_bytes().decode("utf-8")
+    assert result.checksum == await compute_checksum(file_path.read_bytes())
+    assert result.checksum != initial.checksum
+
+
 @pytest.mark.asyncio
 async def test_sync_markdown_file_remains_tuple_compatible(sync_service, test_project):
     """The legacy tuple-returning API still works for existing callers."""