diff --git a/docs/openapi.json b/docs/openapi.json
index a1df080b..6796d369 100644
--- a/docs/openapi.json
+++ b/docs/openapi.json
@@ -2266,7 +2266,10 @@
             "example": "assistant"
           },
           "tool_calls": {
-            "$ref": "#/components/schemas/DeltaToolCall"
+            "type": "array",
+            "items": {
+              "$ref": "#/components/schemas/DeltaToolCall"
+            }
           }
         }
       },