webkitpy should not necessarily autoinstall every module needed by every script. It should autoinstall only modules as they are needed. This is the corresponding FIXME in the code: http://trac.webkit.org/browser/trunk/WebKitTools/Scripts/webkitpy/thirdparty/__init__.py?rev=59350#L39 Fixing this probably means adding a custom import hook like the old autoinstall module. That should let us globally detect whenever an autoinstallable module is being imported from.