Get Complete Package.xml
Below are a few interesting post about preparing package.xml automatically. https://github.com/JitendraZaa/AutoGenerate_Package.xml_Ant http://www.tquila.com/blog/2014/02/11/salesforce-packagexml-builder https://packagebuilder.herokuapp.com/ There is no way to figure out wild card metadata components (*) using API. Also, there is no way to figure out what components are not supported as part of force.com migration tool. Out of above posts, I found Jitendra's post very interesting and useful. Whereas packagebuilder by Tquila guys, generates an exhaustive list of package.xml file for your organization. On a side note Tquila guys have build a few interesting heroku apps. https://sfswitch.herokuapp.com/ - To switch components between orgs. sforgcompare.herokuapp.com - To compare metadata between orgs. Watch this space for more info!