diff --git a/tools/test-proxy/typespec/main.tsp b/tools/test-proxy/typespec/main.tsp
index 672a57c006c..8fef20cf7b8 100644
--- a/tools/test-proxy/typespec/main.tsp
+++ b/tools/test-proxy/typespec/main.tsp
@@ -10,7 +10,7 @@ using TypeSpec.Http;
 namespace TestProxy;
 
 model StartPayload {
-    "x-recording-file"?: string;
+    "x-recording-file": string;
     "x-recording-assets-file"?: string;
 }