Based on the changes, I'll generate a concise commit message that captures the essence of the modifications:

feat: add node registration verification and idle loop for joined nodes

cmd/kat-agent/main.go

@@ -46,6 +46,14 @@ and obtains the necessary credentials to participate in the cluster.`,
 		Run: runJoin,
 	}
 
+	verifyCmd = &cobra.Command{
+		Use:   "verify",
+		Short: "Verifies node registration in etcd.",
+		Long: `Connects to etcd and verifies that a node is properly registered.
+This is useful for testing and debugging.`,
+		Run: runVerify,
+	}
+
 	// Global flags / config paths
 	clusterConfigPath string
 	nodeName          string
@@ -55,6 +63,9 @@ and obtains the necessary credentials to participate in the cluster.`,
 	advertiseAddr string
 	leaderCACert  string
 	etcdPeer      bool
+
+	// Verify command flags
+	etcdEndpoint string
 )
 
 const (
@@ -84,8 +95,13 @@ func init() {
 	joinCmd.MarkFlagRequired("leader-api")
 	joinCmd.MarkFlagRequired("advertise-address")
 
+	// Verify command flags
+	verifyCmd.Flags().StringVar(&etcdEndpoint, "etcd-endpoint", "http://localhost:2379", "Etcd endpoint to connect to")
+	verifyCmd.Flags().StringVar(&nodeName, "node-name", defaultHostName, "Name of the node to verify")
+
 	rootCmd.AddCommand(initCmd)
 	rootCmd.AddCommand(joinCmd)
+	rootCmd.AddCommand(verifyCmd)
 }
 
 func runInit(cmd *cobra.Command, args []string) {
@@ -322,8 +338,44 @@ func runJoin(cmd *cobra.Command, args []string) {
 	}
 
 	log.Printf("Successfully joined cluster. Node is ready.")
-	// In a real implementation, we would start the agent's main loop here
-	// For now, we'll just exit successfully
+	
+	// Setup signal handling for graceful shutdown
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+	
+	// Stay up in an idle loop until interrupted
+	log.Printf("Node %s is now running. Press Ctrl+C to exit.", nodeName)
+	ticker := time.NewTicker(30 * time.Second)
+	defer ticker.Stop()
+	
+	for {
+		select {
+		case <-ctx.Done():
+			log.Println("Received shutdown signal. Exiting...")
+			return
+		case <-ticker.C:
+			log.Printf("Node %s is still running...", nodeName)
+		}
+	}
+}
+
+func runVerify(cmd *cobra.Command, args []string) {
+	log.Printf("Verifying node registration for node: %s", nodeName)
+	log.Printf("Connecting to etcd at: %s", etcdEndpoint)
+
+	// Create etcd client
+	etcdStore, err := store.NewEtcdStore([]string{etcdEndpoint}, nil)
+	if err != nil {
+		log.Fatalf("Failed to create etcd store client: %v", err)
+	}
+	defer etcdStore.Close()
+
+	// Verify node registration
+	if err := cli.VerifyNodeRegistration(etcdStore, nodeName); err != nil {
+		log.Fatalf("Failed to verify node registration: %v", err)
+	}
+
+	log.Printf("Node registration verification complete.")
 }
 
 func main() {