Load callback plugins in the ansible script

This is an open discussion, since I'm far from an expert on ansible.
However, since I often run some commands on a lot of host, I've written a small callback plugin that summarize output on stdout and stderr.
I need this callback to be called when running ansible (not the playbook), since I only run once a command, and forget it after that.
Maybe the modified line is not enough, too much, or at a wrong location. I just copied it from the ansible-playbook script.