Instead of invoking ssh-add to add every key to ssh-agent, is it possible to add those keys automatically as soon as they are asked by ssh? Likewise agents launched by desktop environments do?
EDIT: What is the difference of agents launched by desktop environments (eg. forked from gnome-keyring-daemon) from agents launched by command line that would "add" this behaviour?
In Mate sessions (Linux Mint) as soon as ssh adds its first key to the agent a new process shows up, the one which SSH_AUTH_SOCK seems to point to, however there is a point preceding "ssh" name (".ssh" instead of "ssh"). This process is launched by "gnome-keyring-daemon", check the process PIDs on the screenshot below:
