diff --git a/src/react/useMcp.ts b/src/react/useMcp.ts
index 3f85c66..baaa7f1 100644
--- a/src/react/useMcp.ts
+++ b/src/react/useMcp.ts
@@ -235,7 +235,7 @@ export function useMcp(options: UseMcpOptions): UseMcpResult {
         // Use stable addLog
         addLog('debug', `[Transport] Received: ${JSON.stringify(message)}`)
         // @ts-ignore
-        clientRef.current?.handleMessage(message) // Forward to current client
+        clientRef.current?.handleMessage?.(message) // Forward to current client
       }
       transportInstance.onerror = (err: Error) => {
         // Transport errors usually mean connection is lost/failed definitively for this transport