Guix Home: SSH won't ask for GPG password

[Caleb Herbert]

Guix System.

In home-configuration.scm:
(service home-gpg-agent-service-type
                  (home-gpg-agent-configuration
                   (pinentry-program
                    (file-append pinentry-gnome3 "/bin/pinentry"))
                   (ssh-support? #t)))

caleb@bender ~$ ssh csh@tty.sdf.org
csh@tty.sdf.org's password: 

This shouldn't happen. Pinentry should come up and ask me for my GPG password.

gpg-agent.conf looks normal.

caleb@bender ~$ cat /home/caleb/.gnupg/gpg-agent.conf 
pinentry-program 
/gnu/store/6rlqjdc9ginn4gnkwg8mhqwm015phhrm-pinentry-gnome3-1.2.1/bin/pinentry
default-cache-ttl 600
max-cache-ttl 7200
default-cache-ttl-ssh 1800
max-cache-ttl-ssh 7200
caleb@bender ~$ 

What am I missing?

-- 
Caleb
https://bluehome.net/csh/