if you run a model you made from arctoolbox, in most cases you must also set the stuff you want to display in table as contents as parameter as well as "add to display". If you run it inside modelbuilder it does not have to be a parameter
I don't think this answers the original question of adding "add data" as a TOOL.
"Add to display" would only work for Outputs like shapefiles.
I want 'add data' as a tool/process, so it can take the %value% (hyperlink) from another process (get field value) and add the referenced document to the map.
To elaborate, I have a shapefile of polygons which contain hyperlinks to raster images in one of their fields. I want to select one of these polygons, then have the model follow the hyperlink, add that raster image to the map, and then, apply a particular symbology to that new layer.
(I'm new too, so sorry for rambling