log fix

backend/src/core/logger.py

@@ -205,6 +205,12 @@ def configure_logger(config):
         cot_handler = logging.StreamHandler()
         cot_handler.setFormatter(CotJsonFormatter())
         cot_logger.addHandler(cot_handler)
+
+    # Disable propagation to prevent duplicate output via uvicorn's root logger handlers.
+    # Both loggers have their own dedicated handlers; propagation would cause each message
+    # to appear twice: once via CotJsonFormatter (JSON) and once via uvicorn's DefaultFormatter (text).
+    logger.propagate = False
+    cot_logger.propagate = False
 # #endregion configure_logger