In order to use gpg-agent, you need to install a pinentry dialog.

The following ports of pinentry dialogs are available:

security/pinentry-curses	(ncurses based dialog)
security/pinentry-gtk		(GTK 1.2 based dialog)
security/pinentry-gtk2		(GTK 2.x based dialog)
security/pinentry-qt		(QT based dialog)

