Issue in make a phone call within Google Assistant App - actions-on-google

Question

I try to implement button in basic card i got an error
API Version 2: Failed to parse JSON response string with 'INVALID_ARGUMENT' error: "(expected_inputs[0].input_prompt.rich_initial_prompt.items[1].basic_card.buttons[0].open_url_action) versions: Cannot find field." HTTP Status Code: 200.
conv.ask(new BasicCard({
text: `This is a basic card. Text in a basic card can include "quotes" and`,
subtitle: 'This is a subtitle',
buttons: [
{
"title": "Call",
"openUrlAction": {
"url": "tel:[phone]",
"androidApp": {
"packageName": "com.android.phone"
},
"versions": []
}
},
],
"formattedText": "Some text",
image: new Image({
url: 'https://storage.googleapis.com/actionsresources/logo_assistant_2x_64dp.png',
alt: 'Image alternate text',
}),
"title": "Card Title"
}));
and I tried all the ways add another empty object in button array also same error:
buttons: [
{
"title": "Call",
"openUrlAction": {
"url": "tel:[phone]",
"androidApp": {
"packageName": "com.android.phone"
},
"versions": []
}
},
{}
],
Tried code below got error:
expected_inputs[0].input_prompt.rich_initial_prompt.items[1].basic_card.buttons[0].open_url_action: the protocol must be http or https.
buttons: new Button({
"title": "button text",
'url': "tel:[phone]",
"androidApp": {
"packageName": "com.android.phone"
}
})
got response in action console simulator:
"buttons": [
{
"title": "button text",
"openUrlAction": {
"url": "tel:[phone]"
}
}
]

Answer 1

You cannot open a tel: URL through the Assistant.
As the error noted:
expected_inputs[0].input_prompt.rich_initial_prompt.items[1].basic_card.buttons[0].open_url_action: the protocol must be http or https.
Keep in mind that the Assistant runs on devices that do not support tel: URLs, even if they support https: URLs.

Answer 2

The URL property that you are using includes a phonenumber. The link property can only use links to a webpage. This also comes back in the error message that you are getting:
"the protocol must be http or https.".
So if you want to fix the error, you need to include a http or https link in your button instead of a phonenumber.
As for calling a phonenumber from the Google Assistant App, I'm not sure if this feature is supported at the moment.