How to provide custom message for actions_intent_SIGN_IN?

Question

I want to provide a custom question message for sign-in intent.

For DATETIME we can provide custom message.

{
  "expectUserResponse": true,
  "expectedInputs": [
    {
      "possibleIntents": [
        {
          "intent": "actions.intent.DATETIME",
          "inputValueData": {
            "@type": "type.googleapis.com/google.actions.v2.DateTimeValueSpec",
            "dialogSpec": {
              "requestDatetimeText": "When would you like to schedule the appointment?",
              "requestDateText": "What day was that?",
              "requestTimeText": "What time works for you?"
            }
          }
        }
      ]
    }
  ]
}

For SIGN_IN intent there is no such option.

{
  "expectUserResponse": true,
  "expectedInputs": [
    {
      "possibleIntents": [
        {
          "intent": "actions.intent.SIGN_IN",
          "inputValueData": {
            "@type": "type.googleapis.com/google.actions.v2.SignInValueSpec"
          }
        }
      ]
    }
  ]
}

Answer 1

You'll need an optContent attribute with the custom text you want used for (part of) the sign-in request. So it might be something like

{
  "expectUserResponse": true,
  "expectedInputs": [
    {
      "possibleIntents": [
        {
          "intent": "actions.intent.SIGN_IN",
          "inputValueData": {
            "@type": "type.googleapis.com/google.actions.v2.SignInValueSpec",
            "optContext": "In order to know who you are"
          }
        }
      ]
    }
  ]
}