curl --request GET \
  --url https://eu-gcp-api.vg-stuff.com/v3/agents/{agentId}/variables \
  --header 'Authorization: Bearer <token>'

{
  "success": true,
  "message": "<string>",
  "data": [
    {
      "id": "<string>",
      "in": "<string>",
      "type": "string",
      "value": "<any>",
      "defaultValue": "<any>",
      "key": "<string>",
      "description": "<string>",
      "required": true,
      "reusable": true,
      "isEnv": true,
      "isSystem": true,
      "isGlobal": true,
      "agentId": "<string>",
      "userId": "<string>"
    }
  ]
}