diff --git a/.semversioner/next-release/patch-20250520214513426940.json b/.semversioner/next-release/patch-20250520214513426940.json
new file mode 100644
index 00000000..f6894305
--- /dev/null
+++ b/.semversioner/next-release/patch-20250520214513426940.json
@@ -0,0 +1,4 @@
+{
+  "type": "patch",
+  "description": "Fix global search prompt to include missing formatting key"
+}
diff --git a/graphrag/query/structured_search/global_search/search.py b/graphrag/query/structured_search/global_search/search.py
index b7f75a43..daa7f55c 100644
--- a/graphrag/query/structured_search/global_search/search.py
+++ b/graphrag/query/structured_search/global_search/search.py
@@ -371,7 +371,9 @@ class GlobalSearch(BaseSearch[GlobalContextBuilder]):
             text_data = "\n\n".join(data)
 
             search_prompt = self.reduce_system_prompt.format(
-                report_data=text_data, response_type=self.response_type
+                report_data=text_data,
+                response_type=self.response_type,
+                max_length=self.reduce_max_length,
             )
             if self.allow_general_knowledge:
                 search_prompt += "\n" + self.general_knowledge_inclusion_prompt