How to define values in Action menu command?

Not possible in Action as far as I know, but ExtendScript can set effects via applyEffect.

The following code adds a transform effect that scales the selected item to 200% of its width, based on the top left corner.

/**
  * @File applyEffect sample
  * @3653945.0.0
  * @7111211 sttk3.com
*/

(function() {
  if(app.documents.length <= 0) {return ;}
  var doc = app.documents[0] ;
  var sel = doc.selection ;
  if(sel.length <= 0) {return ;}
  
  var scaleH_Percent = 200 ;
  var scaleV_Percent = 100 ;
  var attrData =
       'R scaleH_Percent ' + scaleH_Percent
    + ' R scaleV_Percent ' + scaleV_Percent
    + ' R scaleH_Factor ' + (scaleH_Percent / 100)
    + ' R scaleV_Factor ' + (scaleV_Percent / 100)
    + ' R moveH_Pts 0'
    + ' R moveV_Pts 0'
    + ' R rotate_Degrees 0'
    + ' R rotate_Radians 0'
    + ' B transformObjects 1'
    + ' B transformPatterns 0'
    + ' B scaleLines 0'
    + ' B reflectX 0'
    + ' B reflectY 0'
    + ' B randomize 0'
    + ' I pinPoint 0'
    + ' I numCopies 0'
  ;
  var xml = <LiveEffect name="Adobe Transform">
      <Dict data={attrData}/>
    </LiveEffect> ;
  XML.prettyPrinting = false ;
  var effectXML = xml.toXMLString() ;

  sel[0].applyEffect(effectXML) ;
})() ;