Permission denied (publickey).

jakes_mac:SomeCode jake$ cap staging deploy
INFO [hkdgad21] Running /usr/bin/env mkdir -p /tmp/somecode/ as jake@example.com
DEBUG [hkdgad21] Command: /usr/bin/env mkdir -p /tmp/somecode/
jake@example.com's password:
INFO [hkdgad21] Finished in 5.166 seconds with exit status 0 (successful).
DEBUG Uploading /tmp/somecode/git-ssh.sh 0.0%
INFO Uploading /tmp/somecode/git-ssh.sh 100.0%
INFO [xyz20312] Running /usr/bin/env chmod +x /tmp/somecode/git-ssh.sh as jake@example.com
DEBUG [xyz20312] Command: /usr/bin/env chmod +x /tmp/somecode/git-ssh.sh
INFO [xyz20312] Finished in 0.240 seconds with exit status 0 (successful).
INFO [abcdef01] Running /usr/bin/env git ls-remote --heads git@github.com:SomeUser/SomeCode.git as jake@example.com
DEBUG [abcdef01] Command: ( GIT_ASKPASS=/bin/echo GIT_SSH=/tmp/somecode/git-ssh.sh /usr/bin/env git ls-remote --heads git@github.com:SomeUser/SomeCode.git )
DEBUG [abcdef01]    Permission denied (publickey).
DEBUG [abcdef01]    fatal: Could not read from remote repository.
DEBUG [abcdef01]
DEBUG [abcdef01]    Please make sure you have the correct access rights
DEBUG [abcdef01]    and the repository exists.
(Backtrace restricted to imported tasks)
cap aborted!
SSHKit::Runner::ExecuteError: Exception while executing as jake@example.com: git exit status: 128
git stdout: Nothing written
git stderr: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

SSHKit::Command::Failed: git exit status: 128
git stdout: Nothing written
git stderr: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Tasks: TOP => git:check
(See full trace by running task with --trace)
The deploy has failed with an error: Exception while executing as jake@example.com: git exit status: 128
git stdout: Nothing written
git stderr: Permission denied (publickey).
fatal: Could not read from remote repository.

ssh-add -A

nano ~/.bash_profile

ssh-add -A 2>/dev/null;

ssh-add -D

eval "$(ssh-agent -s)"

ssh-add ~/.ssh/id_rsa.pub

ssh-add -K

nano ~/.bash_profile

ssh-add -K

sudo nano /etc/ssh/ssh_config

AddKeysToAgent yes

UseKeychain
        On macOS, specifies whether the system should search for
        passphrases in the user's keychain when attempting to use a par-
        ticular key. When the passphrase is provided by the user, this
        option also specifies whether the passphrase should be stored
        into the keychain once it has been verified to be correct.  The
        argument must be ``yes'' or ``no''.  The default is ``no''.

ssh(1): Add an AddKeysToAgent client option which can be set to
   'yes', 'no', 'ask', or 'confirm', and defaults to 'no'.  When
   enabled, a private key that is used during authentication will be
   added to ssh-agent if it is running (with confirmation enabled if
   set to 'confirm').

AddKeysToAgent yes

echo "AddKeysToAgent yes" >> ~/.ssh/config

$ ssh-add -l
The agent has no identities.
$ ssh -T git@bitbucket.org
logged in as davidalger.

You can use git or hg to connect to Bitbucket. Shell access is disabled.
$ ssh-add -l
2048 SHA256:<snip> (RSA)

eval $(ssh-agent -s)
ssh-add ~/.ssh/id_rsa_file