# /usr/lib/systemd/user/ssh-agent.service
[Unit]
Description=SSH key agent
After=local-fs.target
ConditionFileIsExecutable=/usr/bin/ssh-agent

[Service]
Type=forking
Environment=SSH_AUTH_SOCK=%t/ssh-agent.socket
ExecStart=/usr/bin/ssh-agent -a $SSH_AUTH_SOCK

[Install]
WantedBy=default.target