How do I generate a cut-down version of an OpenAPI spec YML (ex. petsore.yaml) using the file itself? - rest

Question

I'd like to use the OpenAPI generator to generate a cut-down version of a OpenAPI spec .yml to build a Postman-esque web application reading these cut-down versions.
Here's an example on what I try to get. I take the standard Petstore spec as an example:
Petstore:
openapi: "3.0.0"
info:
version: 1.0.0
title: Swagger Petstore
license:
name: MIT
servers:
- url: http://petstore.swagger.io/v1
paths:
/pets:
get:
summary: List all pets
operationId: listPets
tags:
- pets
parameters:
- name: limit
in: query
description: How many items to return at one time (max 100)
required: false
schema:
type: integer
format: int32
responses:
'200':
description: A paged array of pets
headers:
x-next:
description: A link to the next page of responses
schema:
type: string
content:
application/json:
schema:
$ref: "#/components/schemas/Pets"
default:
description: unexpected error
content:
application/json:
schema:
$ref: "#/components/schemas/Error"
post:
summary: Create a pet
operationId: createPets
tags:
- pets
responses:
'201':
description: Null response
default:
description: unexpected error
content:
application/json:
schema:
$ref: "#/components/schemas/Error"
/pets/{petId}:
get:
summary: Info for a specific pet
operationId: showPetById
tags:
- pets
parameters:
- name: petId
in: path
required: true
description: The id of the pet to retrieve
schema:
type: string
responses:
'200':
description: Expected response to a valid request
content:
application/json:
schema:
$ref: "#/components/schemas/Pet"
default:
description: unexpected error
content:
application/json:
schema:
$ref: "#/components/schemas/Error"
should generate a fairly similar cut-down spec file looking like this:
- url: /pets
method: GET
title: string
body: null
queryParameters:
- name: limit
defaultValue: 1
required: false
pathVariables: [ ]
- url: /pets/{{petId}}
method: GET
title: string
body: null
queryParameters: [ ]
pathVariables:
- name: petId
defaultValue: 1
required: true
- url: /pets
method: POST
title: string
body: "{ \"id\": \"1\", \"name\": \"Cathy\"}"
queryParameters: [ ]
pathVariables: [ ]
I never worked with mustache templates and didn't find any simple ELI5 tutorials of how to do that and if it's even possible, but I'd need that for multiple API specs as it would be too much of an effort to do and maintain it for every API manually.
How would I go about doing that? Is OpenAPI the right choice or should I go with something different?