review: comments updated

Author: pawbana

intercept/responses/streaming.go

@@ -13,6 +13,7 @@ import (
 	"github.com/coder/aibridge/recorder"
 	"github.com/google/uuid"
 	"github.com/openai/openai-go/v3/responses"
+	oaiconst "github.com/openai/openai-go/v3/shared/constant"
 	"go.opentelemetry.io/otel/attribute"
 )
 
@@ -96,14 +97,16 @@ func (i *StreamingResponsesInterceptor) ProcessRequest(w http.ResponseWriter, r
 	for stream.Next() {
 		ev := stream.Current()
 
-		// not every event has response.id set (eg: fixtures/openai/responses/streaming/simple.txtar).
-		// first event should be of 'response.created' type and have response.id set.
-		// set responseID to response.id of first event that has this field set.
+		// Not every event has response.id set (eg: fixtures/openai/responses/streaming/simple.txtar).
+		// First event should be of 'response.created' type and have response.id set.
+		// Set responseID to the first response.id that is set.
 		if responseID == "" && ev.Response.ID != "" {
 			responseID = ev.Response.ID
 		}
-		// capture the final response from the response.completed event
-		if ev.Type == "response.completed" {
+
+		// Capture the response from the response.completed event.
+		// Only response.completed event type have 'usage' field set.
+		if ev.Type == string(oaiconst.ValueOf[oaiconst.ResponseCompleted]()) {
 			completedEvent := ev.AsResponseCompleted()
 			completedResponse = &completedEvent.Response
 		}