diff --git a/api/server/controllers/agents/request.js b/api/server/controllers/agents/request.js
index d7b4320c1d..f5d8ae6c77 100644
--- a/api/server/controllers/agents/request.js
+++ b/api/server/controllers/agents/request.js
@@ -348,15 +348,19 @@ const ResumableAgentController = async (req, res, next, initializeClient, addTit
 };
 
 /**
- * Non-resumable Agent Controller - Uses GenerationJobManager for abort handling.
- * Response is streamed directly to client via res, but abort state is managed centrally.
+ * Agent Controller - Routes to ResumableAgentController for all requests.
+ * The legacy non-resumable path is kept below but no longer used by default.
  */
 const AgentController = async (req, res, next, initializeClient, addTitle) => {
-  const isResumable = req.query.resumable === 'true';
-  if (isResumable) {
-    return ResumableAgentController(req, res, next, initializeClient, addTitle);
-  }
+  return ResumableAgentController(req, res, next, initializeClient, addTitle);
+};
 
+/**
+ * Legacy Non-resumable Agent Controller - Uses GenerationJobManager for abort handling.
+ * Response is streamed directly to client via res, but abort state is managed centrally.
+ * @deprecated Use ResumableAgentController instead
+ */
+const _LegacyAgentController = async (req, res, next, initializeClient, addTitle) => {
   const {
     text,
     isRegenerate,
diff --git a/api/server/middleware/setHeaders.js b/api/server/middleware/setHeaders.js
index 625c03721b..c1b58e2a5a 100644
--- a/api/server/middleware/setHeaders.js
+++ b/api/server/middleware/setHeaders.js
@@ -1,9 +1,4 @@
 function setHeaders(req, res, next) {
-  // Skip SSE headers for resumable mode - it returns JSON first, then client subscribes separately
-  if (req.query.resumable === 'true') {
-    return next();
-  }
-
   res.writeHead(200, {
     Connection: 'keep-alive',
     'Content-Type': 'text/event-stream',
diff --git a/client/src/hooks/SSE/useResumableSSE.ts b/client/src/hooks/SSE/useResumableSSE.ts
index 3eefcb7d40..ee67c98ed6 100644
--- a/client/src/hooks/SSE/useResumableSSE.ts
+++ b/client/src/hooks/SSE/useResumableSSE.ts
@@ -498,9 +498,7 @@ export default function useResumableSSE(
 
       clearStepMaps();
 
-      const url = payloadData.server.includes('?')
-        ? `${payloadData.server}&resumable=true`
-        : `${payloadData.server}?resumable=true`;
+      const url = payloadData.server;
 
       const maxRetries = 3;
       let lastError: unknown = null;