Ansible has a debugger built in. Let's take a look at how you can build this into your playbook by creating a simple playbook with an error. As we have just mentioned it, we are going to write a playbook that uses the say module. The playbook itself looks as follows:

---

- hosts: localhost
  gather_facts: false
  debugger: "on_failed"

  vars:
    message: "The task has completed and all is well"
    voice: "Daniel"

  tasks:
    - name: Say a message on your Ansible host
      say:
        msg: "{{ massage }}"
        voice: "{{ voice }}"

There are two things to point out: the first being the mistake. As you can see, we are defining a variable named message, but when we come to use it the task, I have made a typo and entered massage instead. Luckily, as I am developing the playbook, I have instructed Ansible to drop to the interactive debugger whenever a task fails.