Thank you for the well done intro and the security risk implied with agent forwarding. I'd be curious how to actually sign with the ssh-agent as you mentioned i

Thank you for the well done intro and the security risk implied with agent forwarding. I'd be curious how to actually sign with the ssh-agent as you mentioned it. I'd also like to know if when OS at login automatically decrypts the default private key, for later use e.g. pushing to github, what would be the risk? Would there be another preferred behaviour?