diff --git a/tests/automation/test_handlers_playlist.py b/tests/automation/test_handlers_playlist.py
index a690d7b6..e13179e3 100644
--- a/tests/automation/test_handlers_playlist.py
+++ b/tests/automation/test_handlers_playlist.py
@@ -738,6 +738,12 @@ class TestSyncPlaylist:
             import time
             time.sleep(0.01)
         assert len(sync_calls) == 1
+        # #823 — the handler must NOT force a sync mode; it leaves it unset so
+        # _run_sync_task resolves the user's configured global mode (else the
+        # automated sync always 'replace'd and wiped the playlist image/desc).
+        args, kwargs = sync_calls[0]
+        assert kwargs.get('sync_mode') is None      # not forced via kwarg
+        assert len(args) == 6                        # no 7th positional sync_mode either
 
     def test_organize_by_playlist_passes_skip_wishlist_add(self):
         discovered_track = {
diff --git a/tests/test_playlist_edit.py b/tests/test_playlist_edit.py
index 8cc0e10d..66caae40 100644
--- a/tests/test_playlist_edit.py
+++ b/tests/test_playlist_edit.py
@@ -138,6 +138,15 @@ def test_normalize_keeps_reconcile_from_config():
     assert normalize_sync_mode('', 'reconcile') == 'reconcile'
 
 
+def test_normalize_keeps_append_from_config():
+    # #823 — an AUTOMATED sync (mirrored auto-sync / Playlist Pipeline) passes no
+    # per-request mode, so it must resolve to the user's configured global mode
+    # instead of hardcoding 'replace' (which recreated the playlist + wiped its
+    # image/description). Default 'replace' users are unaffected.
+    assert normalize_sync_mode(None, 'append') == 'append'
+    assert normalize_sync_mode(None, 'replace') == 'replace'
+
+
 def test_normalize_request_overrides_config():
     assert normalize_sync_mode('append', 'reconcile') == 'append'
     assert normalize_sync_mode('reconcile', 'replace') == 'reconcile'
diff --git a/web_server.py b/web_server.py
index b4c537a2..9e7bc148 100644
--- a/web_server.py
+++ b/web_server.py
@@ -24136,9 +24136,20 @@ def _run_sync_task(
     automation_id=None,
     profile_id=1,
     playlist_image_url='',
-    sync_mode='replace',
+    sync_mode=None,
     skip_wishlist_add=False,
 ):
+    # When a caller doesn't specify a mode — the mirrored auto-sync + Playlist
+    # Pipeline (auto_sync_playlist), iTunes-link sync, Wing It — honor the user's
+    # configured global "Playlist sync mode" instead of hardcoding 'replace'.
+    # Hardcoding replace meant every AUTOMATED sync recreated the server
+    # playlist, wiping its custom image + description even when the user chose
+    # Append/Reconcile (#823 carlosjfcasero). The global default is still
+    # 'replace', so default users are unaffected; only users who set
+    # Append/Reconcile get the change. (Mirrors _submit_sync_task.)
+    if sync_mode is None:
+        from core.sync.playlist_edit import normalize_sync_mode
+        sync_mode = normalize_sync_mode(None, config_manager.get('playlist_sync.mode', 'replace'))
     return _discovery_sync.run_sync_task(
         playlist_id, playlist_name, tracks_json, automation_id, profile_id, playlist_image_url,
         _build_sync_deps(),