Update app.py

app.py

@@ -27,7 +27,7 @@ def _generate(text: str):
 
 @app.mcp.tool(name="summarize")
 @app.api(name="summarize", concurrency_limit=1, stream_every=0.2)
-def summarize(text: str):
+def summarize(text: str) -> str:
     """Summarize the input text into 3 bullet points."""
     out = ""
     for chunk in _generate(text):