diff --git a/src/claude_memory/api/app.py b/src/claude_memory/api/app.py
index 954c3d3..982a54e 100644
--- a/src/claude_memory/api/app.py
+++ b/src/claude_memory/api/app.py
@@ -45,7 +45,7 @@ UI_DIR = pathlib.Path(__file__).parent.parent / "ui" / "static"
 
 
 @app.get("/")
-async def ui_root():
+async def ui_root() -> FileResponse:
     """Serve the UI single-page app."""
     return FileResponse(UI_DIR / "index.html")