Use automation to execute ssh command

So how would I use an automation to send a command to the terminal ssh addon? And I’m still not sure which terminal addon has this option.

Here’s what I put

service: hassio.addon_stdin
data:
addon: core_ssh
input: ha core update

I assumed this was sufficient to get it to send commands, this did not work though. Is this not the correct way to send commands to the ssh addon?