diff --git a/src/server/streamableHttp.test.ts b/src/server/streamableHttp.test.ts
index 7cb062bc..efd5de1c 100644
--- a/src/server/streamableHttp.test.ts
+++ b/src/server/streamableHttp.test.ts
@@ -1000,7 +1000,7 @@ describe("StreamableHTTPServerTransport with resumability", () => {
     const eventId = idMatch![1];
     expect(storedEvents.has(eventId)).toBe(true);
     const storedEvent = storedEvents.get(eventId);
-    expect(eventId.startsWith('standalonesse')).toBe(true);
+    expect(eventId.startsWith('_GET_stream')).toBe(true);
     expect(storedEvent?.message).toMatchObject(notification);
   });
 
diff --git a/src/server/streamableHttp.ts b/src/server/streamableHttp.ts
index 58d0fe14..7ddfa3ab 100644
--- a/src/server/streamableHttp.ts
+++ b/src/server/streamableHttp.ts
@@ -96,7 +96,7 @@ export class StreamableHTTPServerTransport implements Transport {
   private _requestResponseMap: Map<RequestId, JSONRPCMessage> = new Map();
   private _initialized: boolean = false;
   private _enableJsonResponse: boolean = false;
-  private _standaloneSseStreamId: string = 'standalonesse';
+  private _standaloneSseStreamId: string = '_GET_stream';
   private _eventStore?: EventStore;
 
   sessionId?: string | undefined;