diff --git a/automotive/vehicle/aidl/emu_metadata/android.hardware.automotive.vehicle-types-meta.json b/automotive/vehicle/aidl/emu_metadata/android.hardware.automotive.vehicle-types-meta.json
index f07dbc1..7be7cf1 100644
--- a/automotive/vehicle/aidl/emu_metadata/android.hardware.automotive.vehicle-types-meta.json
+++ b/automotive/vehicle/aidl/emu_metadata/android.hardware.automotive.vehicle-types-meta.json
@@ -322,7 +322,7 @@
                     "VehicleHvacFanDirection"
                 ],
                 "data_enum": "VehicleHvacFanDirection",
-                "description": "Fan direction setting\nThis property is defined as VehiclePropertyAccess.READ_WRITE, but OEMs have the option to implement it as VehiclePropertyAccess.READ only."
+                "description": "Fan direction setting\nThis property is defined as VehiclePropertyAccess.READ_WRITE, but OEMs have the option to implement it as VehiclePropertyAccess.READ only.\nThe supported hvac fan direction is exposed through {@code HVAC_FAN_DIRECTION_AVAILABLE} property. Caller should not call {@code getSupportedValuesList}, or use {@code VehicleAreaConfig#supportedEnumValues}."
             },
             {
                 "name": "HVAC current temperature.",
diff --git a/automotive/vehicle/aidl_property/android/hardware/automotive/vehicle/VehicleProperty.aidl b/automotive/vehicle/aidl_property/android/hardware/automotive/vehicle/VehicleProperty.aidl
index 56cbbb3..8e653c5 100644
--- a/automotive/vehicle/aidl_property/android/hardware/automotive/vehicle/VehicleProperty.aidl
+++ b/automotive/vehicle/aidl_property/android/hardware/automotive/vehicle/VehicleProperty.aidl
@@ -959,6 +959,10 @@
      * This property is defined as VehiclePropertyAccess.READ_WRITE, but OEMs have the option to
      * implement it as VehiclePropertyAccess.READ only.
      *
+     * The supported hvac fan direction is exposed through {@code HVAC_FAN_DIRECTION_AVAILABLE}
+     * property. Caller should not call {@code getSupportedValuesList}, or use
+     * {@code VehicleAreaConfig#supportedEnumValues}.
+     *
      * @change_mode VehiclePropertyChangeMode.ON_CHANGE
      * @access VehiclePropertyAccess.READ_WRITE
      * @access VehiclePropertyAccess.READ