[capink]

The custom action below would store clipboard contents into a chain variable called clipboard:

from qt.core import QApplication
from calibre_plugins.action_chains.actions.base import ChainAction

class PasteClipboardAction(ChainAction):

    name = 'Paste Clipboard'

    def run(self, gui, settings, chain):
        chain.set_chain_vars({'clipboard': QApplication.clipboard().text()})

You can access that using the following template

program:
    globals(clipboard)