vars_prompt not working in role - Ansible - ansible

Question

I'm trying to automate hostname creation for 10x machines using ansible roles. What I want when executing playbook, as this wait for enter the user name manually.
I tried with vars_prompt module for satisfying the requirement. But here for a single *.yml file, I'm able to see the expected results
Without role - I can see the input is taken to variable host. but this works fine.
#host.yml .
---
- hosts: ubuntu
user: test
sudo: yes
vars_prompt:
- name: host
prompt: "Specify host name?"
private: no
tasks:
- debug:
msg: ' log as {{ host }}'
- name: Changing hostname
hostname:
name: '{{ host }}'
With role, < this is not working > { vars_prompt not working }
#role.yml
---
- hosts: ubuntu
user: test
sudo: yes
roles:
# - hostname
#hostname/tasks/main.yml
- name: testing prompt
vars_prompt:
- name: host
prompt: "Specify host name?"
- name: Ansible prompt example
debug:
msg: "{{ host }}"
#Changing hostname
- name: Changing hostname
hostname:
name: "{{ host }}"
Here I'm getting error as
ERROR! no action detected in task. This often indicates a misspelled module name, or incorrect module path.
The error appears to have been in '/root/roles/hostname/tasks/main.yml': line 1, column 3, but may
be elsewhere in the file depending on the exact syntax problem.
The offending line appears to be:
- name: testing prompt
^ here
My expectation is to set some parameters need to set manually as input while the execution of playbook. Need to work this vars_prompt module in role.

Answer 1

Run 1st play with serial: 1 and enter the hostnames. 2nd play (in the same playbook) will use the facts.
- hosts: ubuntu
serial: 1
user: test
sudo: yes
tasks:
- pause:
prompt: "Specify hostname for {{ inventory_hostname }}?"
echo: yes
register: result
- set_fact:
host: "{{ result.user_input }}"
- hosts: ubuntu
user: test
sudo: yes
roles:
- hostname