Update app.py

app.py

@@ -1,15 +1,20 @@
 
-# ---------- MUST BE FIRST: Gradio CDN + ZeroGPU probe ----------
 import os
 os.environ.setdefault("GRADIO_USE_CDN", "true")
 
 import spaces
 
 @spaces.GPU(duration=10)
-def _gpu_probe(a: int = 1, b: int = 1) -> int:
+def gpu_probe(a: int = 1, b: int = 1) -> int:
     # Never called; exists so ZeroGPU startup check passes.
     return a + b
 
+
+@spaces.GPU(duration=10)
+def gpu_echo(x: str = "ok") -> str:
+    return x
+
+
 # ---------- Standard imports ----------
 from pathlib import Path
 from typing import Optional, Tuple, List