diff --git a/docs/exts/substitution_extensions.py b/docs/exts/substitution_extensions.py
index cdacab22919a85..738c30d35631d9 100644
--- a/docs/exts/substitution_extensions.py
+++ b/docs/exts/substitution_extensions.py
@@ -89,7 +89,7 @@ def condition(node):
 def substitution_code_role(*args, **kwargs) -> tuple[list, list[SystemMessage]]:
     """Decorate an inline code so that SubstitutionCodeBlockTransform will notice it"""
     [node], system_messages = code_role(*args, **kwargs)
-    node[_SUBSTITUTION_OPTION_NAME] = True
+    node[_SUBSTITUTION_OPTION_NAME] = True  # type: ignore[index]
 
     return [node], system_messages