diff --git a/backend/backend.proto b/backend/backend.proto
index 85e872607a38..1a3dc49db526 100644
--- a/backend/backend.proto
+++ b/backend/backend.proto
@@ -157,6 +157,7 @@ message Reply {
   bytes message = 1;
   int32 tokens = 2;
   int32 prompt_tokens = 3;
+  string audio_output = 4;
 }
 
 message ModelOptions {
diff --git a/core/backend/llm.go b/core/backend/llm.go
index 199a62338c84..3f44878bd93a 100644
--- a/core/backend/llm.go
+++ b/core/backend/llm.go
@@ -23,8 +23,9 @@ import (
 )
 
 type LLMResponse struct {
-	Response string // should this be []byte?
-	Usage    TokenUsage
+	Response    string // should this be []byte?
+	Usage       TokenUsage
+	AudioOutput string
 }
 
 type TokenUsage struct {