Irradicate Gnome Keyring SSH agent
Why? Because it doesn't work with ed25519 keys and utterly takes over the ability run the real one globally.
Disable gnome keyring starting ssh-agent "support"
Copy the default desktop autostart file to local configuration for user:
cp -piv /etc/xdg/autostart/gnome-keyring-ssh.desktop ~/.config/autostart/
Edit the file and add X-GNOME-Autostart-enabled=false to the end of it. It should end up like this:
[Desktop Entry] Type=Application Name=SSH Key Agent Comment=GNOME Keyring: SSH Agent Exec=/usr/bin/gnome-keyring-daemon --start --components=ssh OnlyShowIn=GNOME;Unity;MATE; X-GNOME-Autostart-Phase=Initialization X-GNOME-AutoRestart=false X-GNOME-Autostart-Notify=true X-GNOME-Bugzilla-Bugzilla=GNOME X-GNOME-Bugzilla-Product=gnome-keyring X-GNOME-Bugzilla-Component=general X-GNOME-Bugzilla-Version=3.10.1 X-Ubuntu-Gettext-Domain=gnome-keyring X-GNOME-Autostart-enabled=false
Start normal ssh-agent and export env
Add our own upstart session script which runs the real one.
.. or just let /usr/share/upstart/sessions/ssh-agent.conf run. This hasn't been running up until now because gnome-ssh-agent has been running before it, screwing things up.