Hi Jason,
param section supports embedded Java code expressions. Try this option.
<item name="url target">
<action>
<launch-browser>
<url>http://url/file/?name={0}</url>
<param>
<expression>
(((String)attr(AttributeID.MODEL_NAME)).split("\\."))[0]
</expression>
</param>
</launch-browser>
</action>
</item>
Regards