diff --git a/chat.go b/chat.go
index 33b8755..efb14fd 100644
--- a/chat.go
+++ b/chat.go
@@ -225,8 +225,8 @@ const (
 )
 
 type Tool struct {
-	Type     ToolType           `json:"type"`
-	Function FunctionDefinition `json:"function,omitempty"`
+	Type     ToolType            `json:"type"`
+	Function *FunctionDefinition `json:"function,omitempty"`
 }
 
 type ToolChoice struct {
diff --git a/examples/completion-with-tool/main.go b/examples/completion-with-tool/main.go
index 2c7fedc..26126e4 100644
--- a/examples/completion-with-tool/main.go
+++ b/examples/completion-with-tool/main.go
@@ -35,7 +35,7 @@ func main() {
 	}
 	t := openai.Tool{
 		Type:     openai.ToolTypeFunction,
-		Function: f,
+		Function: &f,
 	}
 
 	// simulate user asking a question that requires the function