a polkit agent in 145 lines of code, because polkit is dumb and none of the other agents worked
GPL-3.0 License
polkit is dumb, and never works.
so here is probably the simplest version you can have (except the first one that just ACKed every call), 97 lines of C++ and 45 lines of C, in total 142 lines of code.
it just uses kdesu to call a helper as root to send the reply, so all requests requires the user to enter the root password.
Write a simple replacement for polkit itself, it's a simple dbus API and 90% of what it provides is never used.