diff --git a/src/calibre/ebooks/mobi/output.py b/src/calibre/ebooks/mobi/output.py
index c41a54165d..49da18ea7b 100644
--- a/src/calibre/ebooks/mobi/output.py
+++ b/src/calibre/ebooks/mobi/output.py
@@ -36,7 +36,7 @@ class MOBIOutput(OutputFormatPlugin):
             recommended_value=False, level=OptionRecommendation.LOW,
             help=_('Disable compression of the file contents.')
         ),
-        OptionRecommendation(name='personal_doc', recommended_value='[kindle_pdoc]',
+        OptionRecommendation(name='personal_doc', recommended_value='[PDOC]',
             help=_('Tag marking book to be filed with Personal Docs')
         ),
     ])