Added Custom Scope to passwordless grant

Hi All,

I am trying to create custom flow within passwordless grant type, however I am getting scope not allowed error. Any suggestion?

    "grant_type": "",
    "client_id": "xxxx",
    "client_secret": "xxx",
    "otp": "12345",
    "realm": "sms",
    "username": "+123232323",
    "audience": "",
    "scope": "openid",
    "redirect_uri": ""

The solution I am seeking is to distinct access token based on flow so that can restrict the access token usage as per my defined flow.