When I'm running Gnome, ssh-agent will run ssh-add upon slogin/ssh if the identity is not loaded. I want to mimic this behavior on remote shells, but everything I find suggests to run ssh-add upon login. I only want to run ssh-add if I subsequently run slogin/ssh on the remote shell, not every time I login.
I worked out a solution for this via the bash shell.
Add to .bashrc: