Using field created in ModelBuilder in same model?

I have created a model in ArcGIS ModelBuilder and in a point of the process I insert a python tool (New Field) to create new field in a shapefile.

After that I want to use this new field in other tool in the same model. But I cannot use it because it is not created, it is not selectable in the available fields of the shapefile.

This image shows a part of the model where I create the new field and after I want to use this new field as a input in Pivot Table tool.

The New Field toll python code is:

def getParameterInfo(self):
    """Define parameter definitions"""

# First parameter

    param0 = arcpy.Parameter(
        displayName="Shape entrada",
        name="in_features",
        datatype="GPTableView",
            parameterType="Required",
        direction="Input")


    parameters = [param0]
    return parameters

def isLicensed(self):
    """Set whether tool is licensed to execute."""
    return True
def updateParameters(self, parameters):return
def updateMessages(self, parameters):return

def execute(self, parameters, messages):
    """The source code of the tool."""

#-----------------------------
camp= "GROUP_"
val= "Pix_Value"

    a= parameters[0].valueAsText

arcpy.AddField_management(a, camp, "TEXT", "", "", "", "", "NULLABLE", "NON_REQUIRED", "")
arcpy.AddField_management(a, val, "SHORT", "", "", "", "", "NULLABLE", "NON_REQUIRED", "")
#-----------------------------


with arcpy.da.UpdateCursor(a, ["CODE2012",camp, val]) as cursor:
    for row in cursor:
        a= int(row[0])
        if a < 12100:
                    row[1] = "Residential"
            row[2]= 5
            elif a==12100 or a==12300 or a==12400:
                    row[1] = "Industrial"
            row[2]= 4
            elif a>12100 and a<12300:
                    row[1] = "Highway"
            row[2]= 6
            elif a == 21000:
                row[1] = "AnnualCrop"
            row[2]= 1
        elif a == 22000 or a== 25000:
                row[1] = "PermanentCrop"
            row[2]=2
        elif a == 23000:
                row[1] = "Pasture"
            row[2]=3
        elif a == 31000:
                row[1] = "Forest"
            row[2]=8
        elif a == 32000:
                row[1] = "HerbaceousVegetation"
            row[2]=9
        elif a == 50000:
                row[1] = "Water"
            row[2]=7
        else:
            row[1]= "No_clasified"
            row[2]=0


        cursor.updateRow(row)
    del a
    del cursor`