as the title say，if export var a，now how to write the a attribute description

    cybereality When the mouse stops on the editor node, it will prompt the description of the attribute. How can I set this description

      cybereality No, this is not supported, but it looks like it was worked on and never merged.
      https://github.com/godotengine/godot/pull/35716

      I could have sworn there was some discussion on this wrt godot 4 @attributes but I don't recall what came of it.
      Looks like _get_property_list() can define hint and hint_string tho:
      https://docs.godotengine.org/en/latest/classes/class_object.html#class-object-method-get-property-list

      The example isn't written out like above but seems this should be possible in godot 3.6 and below as well:
      https://docs.godotengine.org/en/3.6/classes/class_object.html#class-object-method-get-property-list

          Thank you, respondents，It is not supported in 3. x, but has been implemented in 4. x, and is defined using ##