arcpy.AddField_management does not work in tool, only in Python Interpreter

Question

I am creating a tool in ArcGIS Pro where a part of the code creates a feature class (low_fuel_warning) and adds fields to it. When running the code in the Jupyter Notebook in ArcGIS, it works as it should. However, when running the code in a tool, it only creates a feature class but fails to add any fields.

What could the reason behind this be?

workspace = path to workspace

#  Create feature class low_fuel_warning
low_fuel_warning = arcpy.CreateFeatureclass_management(out_path=workspace, out_name="low_fuel_warning", geometry_type="POINT", template=[], has_m="DISABLED", has_z="DISABLED", spatial_reference="", config_keyword="", spatial_grid_1=0, spatial_grid_2=0, spatial_grid_3=0, out_alias="")

# Add field "fuel level", "distance", and "origin" to feature class
low_fuel_warning = arcpy.AddField_management(in_table="low_fuel_warning", field_name="fuel_level", field_type="DOUBLE", field_precision=None, field_scale=None, field_length=None, field_alias="", field_is_nullable="NULLABLE", field_is_required="NON_REQUIRED", field_domain="")

low_fuel_warning = arcpy.AddField_management(in_table="low_fuel_warning", field_name="distance", field_type="DOUBLE", field_precision=None, field_scale=None, field_length=None, field_alias="", field_is_nullable="NULLABLE", field_is_required="NON_REQUIRED", field_domain="")

low_fuel_warning = arcpy.AddField_management(in_table="low_fuel_warning", field_name="origin", field_type="TEXT", field_precision=None, field_scale=None, field_length=None, field_alias="", field_is_nullable="NULLABLE", field_is_required="NON_REQUIRED", field_domain="")[0]

Answer 1

Your field origin cannot have a field length of None it must be X number of characters. Also and I see this regularly in beginner coders is that they give a misleading name to the result object and treat it as dataset. So in your code low_fuel_warning is actually a result object as all geoprocessing tools return result objects which have their own set of properties. You also don't appear to be even using it, so why even reference it? I would recommend you call it something like resObj so its explicit as what it is and easier to understand.