Write a playbook, which access the network devices present in host file and check for host OS of the device (nexus/cisco/arista) - networking

Question

I am writing a playbook, which dynamically enters the network servers provided by user at prompt in host file.Further i want to create a task which will ssh on the server one by one and run show version command to fetch the OS of those network devices.
As of now, I am getting the below error:
1."Unable to automatically determine host network os. Please manually configure ansible_network_os value for this host"
I dont want to define the OS beforehand, rather want the playbook to do it.
I tried entering some configurations in host file as below:
[device]
192.1xx.xxx.xx
[all:vars]
ansible_connection=network_cli
ansible_user=user
ansible_ssh_pass=password
ssh_args = -o GSSAPIAuthentication=no
The below plsybook is taking device name from the user and adding it to the file, further it need to ssh on those servers and fetch the OS details:
---
- name: add host dynamically
hosts: localhost
gather_facts: no
vars:
Server: null_val1
vars_prompt:
- name: "Server"
prompt: "Please enter the non-reporting server/IP"
private: no
default: null_val1
pre_tasks:
- name: Save variable
set_fact:
Server: "{{Server}}"
- name: Copying servers to host file
hosts: localhost
become: true
tasks:
- name: copying variable value
lineinfile:
path: "{{playbook_dir}}/hosts.txt"
line: "{{Server}}"
insertafter: '^\[device\]'
state: present
- name: Main execution task
hosts: device
gather_facts: true
tasks:
- name: Run command on devices
cli_command:
command: show version
register: result
- name: display result
debug:
var: result.stdout_lines
The actual result should show me the OS of network device(s) entered in host file by running show version command remotely.