a.yaml

openapi: "3.0.0"
info:
  version: 1.0.0
  title: Swagger Petstore
  license:
    name: MIT
servers:
  - url: https://example.com
paths:
  /pets:
    get:
      parameters:
        - name: limit
          in: query
          required: false
          schema:
            type: integer
            maximum: 20
      responses:
        "200":
          description: ""
          headers:
            x-next:
              schema:
                type: string
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Pets"
    post:
      requestBody:
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/Pet"
      responses:
        "201":
          description: ""
components:
  schemas:
    Pet:
      type: object
      required:
        - id
        - name
      properties:
        id:
          type: integer
        name:
          type: string
          minLength: 3
          maxLength: 10
    Pets:
      type: array
      items:
        $ref: "#/components/schemas/Pet"