There's also something weird going on with "-o BatchMode=yes", which is used by shells to tab-complete remote files for scp and rsync.<p>I could ssh into a server without typing the ssh key password, but zsh refused to tab-complete scp and rsync command lines. Turns out it was using "ssh -o BatchMode=yes servername somethingsomething" to retrieve a list of files, but "-o BatchMode=yes" prevented whatever magic is happening from unlocking the ssh key. Figuring this out was tricky because dtruss and lldb refused to attach to /bin/zsh and /usr/bin/ssh because of SIP. (In fact, "dtruss --help" lists "dtruss df -h" as the first example, something that doesn't even work on sierra because /bin/df is protected by SIP)<p>The fix is to run "ssh-add -A" after booting. Very odd, since there are no password prompts involved anywhere.