Run Command on Another Server and register output on variable

instal.sh

#!/bin/bash

ansible-playbook -i "localhost," -c local playbook.yml 

playbook.yml

# https://stackoverflow.com/questions/33896847/how-do-i-set-register-a-variable-to-persist-between-plays-in-ansible
- hosts: all
  tasks:   
    - command: /bin/echo "this is a test"
      delegate_to: localhost
      register: foo
    - debug: var=foo
    - debug: 
        msg: "{{ foo['stdout'] }}"