diff --git a/agent-node/bootstrap_installer.py b/agent-node/bootstrap_installer.py
index 19c8676..eed5f12 100644
--- a/agent-node/bootstrap_installer.py
+++ b/agent-node/bootstrap_installer.py
@@ -190,7 +190,10 @@
             pass
 
     hub_url   = args.hub   or existing_config.get("hub_url", DEFAULT_HUB)
-    token     = args.token or existing_config.get("auth_token") or os.getenv("AGENT_AUTH_TOKEN", "")
+    
+    # NEW: The update endpoint requires the hub's secret key, not the node's specific invite/auth token
+    token = args.token or existing_config.get("secret_key") or existing_config.get("auth_token") or os.getenv("AGENT_AUTH_TOKEN", "")
+    
     node_id   = args.node_id or existing_config.get("node_id", "cortex-node-001")
     grpc      = args.grpc or existing_config.get("grpc_endpoint") or hub_url.replace("https://", "").replace("http://", "") + ":50051"
     install_dir = args.install_dir