DialogFlow: Missing "user" property in JSON after successful Google Account linking - actions-on-google

Question

So after successful Google Account linking in my app, I tested it using an Android device without any problem. I used the "in conversation prompt" technique to request the user to authenticate to proceed further. In other words, I was successfully able to receive the "user" property of response from Dialogflow with valid accessToken (among other info).
Now, I tried it on a Google Home device. The device is configured with the same email Id I used on the Android mobile device. The G.Home successfully loads the app when I invoke it. But the missing part here is the accessToken in the user property (JSON below). I have assumed the following in the above scenario:
Since I have already signed in successfully on the Android mobile device, the next time I try to invoke the app on the same device, the app doesn't prompts for the "sign in" because it already has the accessToken (until it is expired). And since I am using the same gmail address on the G. Home device, I should have gotten the same accessToken as well.
As long as the same gmail address is used, it doesn't matter what device/surface I use to Google auth myself, I will always get the accessToken if it has not expired.
The setup/configuration for the whole Google Account linking is detailed in the above link I've shared. Here is the JSON I've received on G. Home and Android device respectively:
{
"originalRequest": {
"source": "google",
"version": "2",
"data": {
"isInSandbox": true,
"surface": {
"capabilities": [
{
"name": "actions.capability.MEDIA_RESPONSE_AUDIO"
},
{
"name": "actions.capability.AUDIO_OUTPUT"
}
]
},
"inputs": [
{
"rawInputs": [
{
"query": "continue",
"inputType": "VOICE"
}
],
"arguments": [
{
"rawText": "continue",
"textValue": "continue",
"name": "text"
}
],
"intent": "actions.intent.TEXT"
}
],
"user": {
"lastSeen": "2018-07-17T10:33:57Z",
"locale": "en-US",
"userId": "15229245xxx"
},
"conversation": {
"conversationId": "153182806xxx",
"type": "ACTIVE",
"conversationToken": "[\"disclaimer_option\"]"
},
"availableSurfaces": [
{
"capabilities": [
{
"name": "actions.capability.SCREEN_OUTPUT"
},
{
"name": "actions.capability.AUDIO_OUTPUT"
},
{
"name": "actions.capability.WEB_BROWSER"
}
]
}
]
}
},
"id": "9459d297-4746-4ffe-99fa-xxx",
"timestamp": "2018-07-17T11:49:02.693Z",
"lang": "en-us",
"result": {
"source": "agent",
"resolvedQuery": "continue",
"speech": "",
"action": "v00.authentication.pin",
"actionIncomplete": false,
"parameters": {
"CallEnum": "Login"
},
"contexts": [
{
"name": "disclaimer_option",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 0
},
{
"name": "pin",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 1
},
{
"name": "google_assistant_input_type_voice",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 0
},
{
"name": "actions_capability_audio_output",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 0
},
{
"name": "actions_capability_media_response_audio",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 0
}
],
"metadata": {
"intentName": "v00.authentication.pin",
"isResponseToSlotfilling": false,
"intentId": "146f0d7d-0194-43cb-90e4-xxx",
"webhookUsed": "true",
"webhookForSlotFillingUsed": "false",
"nluResponseTime": 87
},
"fulfillment": {
"speech": "",
"messages": []
},
"score": 1
},
"status": {
"code": 200,
"errorType": "success"
},
"sessionId": "15318280xxx"
}
and
{
"originalRequest": {
"source": "google",
"version": "2",
"data": {
"isInSandbox": true,
"surface": {
"capabilities": [
{
"name": "actions.capability.MEDIA_RESPONSE_AUDIO"
},
{
"name": "actions.capability.WEB_BROWSER"
},
{
"name": "actions.capability.AUDIO_OUTPUT"
},
{
"name": "actions.capability.SCREEN_OUTPUT"
}
]
},
"inputs": [
{
"rawInputs": [
{
"query": "Continue",
"inputType": "TOUCH"
}
],
"arguments": [
{
"rawText": "Continue",
"textValue": "Continue",
"name": "text"
}
],
"intent": "actions.intent.TEXT"
}
],
"user": {
"lastSeen": "2018-07-17T09:44:08Z",
"accessToken": "6IlPNz0YFb_stP0quM1xxx",
"locale": "en-US",
"userId": "15229245xxx"
},
"conversation": {
"conversationId": "153182082xxx",
"type": "ACTIVE",
"conversationToken": "[\"disclaimer_option\"]"
},
"availableSurfaces": [
{
"capabilities": [
{
"name": "actions.capability.WEB_BROWSER"
},
{
"name": "actions.capability.AUDIO_OUTPUT"
},
{
"name": "actions.capability.SCREEN_OUTPUT"
}
]
}
]
}
},
"id": "ae2e3ff8-f351-497b-9429-xxx",
"timestamp": "2018-07-17T09:47:54.999Z",
"lang": "en-us",
"result": {
"source": "agent",
"resolvedQuery": "Continue",
"speech": "",
"action": "v00.authentication.pin",
"actionIncomplete": false,
"parameters": {
"CallEnum": "Login"
},
"contexts": [
{
"name": "google_assistant_input_type_touch",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 0
},
{
"name": "pin",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 1
},
{
"name": "disclaimer_option",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 0
},
{
"name": "actions_capability_screen_output",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 0
},
{
"name": "actions_capability_audio_output",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 0
},
{
"name": "actions_capability_media_response_audio",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 0
},
{
"name": "actions_capability_web_browser",
"parameters": {
"CallEnum": "Login",
"CallEnum.original": ""
},
"lifespan": 0
}
],
"metadata": {
"intentName": "v00.authentication.pin",
"isResponseToSlotfilling": false,
"intentId": "146f0d7d-0194-43cb-90e4-xxx",
"webhookUsed": "true",
"webhookForSlotFillingUsed": "false",
"nluResponseTime": 87
},
"fulfillment": {
"speech": "",
"messages": []
},
"score": 1
},
"status": {
"code": 200,
"errorType": "success"
},
"sessionId": "153182082xxx"
}
My question is, where can I get the accessToken when I am using the Google Home device?