diff --git a/types/chat.go b/types/chat.go
index cf87d787..f746dbad 100644
--- a/types/chat.go
+++ b/types/chat.go
@@ -12,9 +12,9 @@ type ChatCompletionToolCallsFunction struct {
 
 type ChatCompletionToolCalls struct {
 	Id       string                          `json:"id"`
-	Index    int                             `json:"index,omitempty"`
 	Type     string                          `json:"type"`
 	Function ChatCompletionToolCallsFunction `json:"function"`
+	Index    int                             `json:"index"`
 }
 
 type ChatCompletionMessage struct {