fallback intent not invoked from Carousel (Actions on Google) - webhooks

Question

I am connecting Actions on Google (on my Android) to my webhook via API.AI
When a user orders, say pizza online, API.AI creates a fallback intent and the webhook sends a json with Carousel.
This works fine. If user clicks on Carousel item, the response is sent to webhook too.
I am responding to that click by asking "How many pizzas" and use a suggestion chip.
However, no fallback intent is activated in API.AI and the app crashes.
Earlier, I was giving a simple text response to carousel select "Thanks for the order" and it was working.
Can someone help me solve this problem?
I realize that the problem is not in API.AI or fallback intent but in JSON I am sending. If I reply to user's selection in Carousel with a simple text/speech response it works. It also works if I send a Carousel chip again. However, if I try to send a list or card, it crashes. Perhaps, I don't have right json formatting for them.
If someone has any json sent by their webhook (working with API.AI) for list/suggestion chip or card, it would be very helpful!
#matthewayne When I send the following as a reply (json), it works:
speech = "Thank you. People also looked at these:"
print(speech)
webhook_result={
"speech": speech,
"contextOut": [
{
"name": "_actions_on_google_,complementary",
"lifespan": 100,
"parameters": {}
}
],
"data": {
"google": {
"expectUserResponse": True,
"richResponse": {
"items": [
{
"simpleResponse": {
"textToSpeech": speech
}
}
],
"suggestions": []
},
"systemIntent": {
"intent": "actions.intent.OPTION",
"data": {
"#type": "type.googleapis.com/google.actions.v2.OptionValueSpec",
"carouselSelect": {}
}
}
}
}
}
I also populate carouselSelect with list of things in carousel. But if I change it to listSelect, and respond, it crashes.
When I say crash, it means that Google says that my app has stopped responding.
It would be very helpful to have a template or sample listResponse json.

Answer 1

After a carousel response is sent to the user the next request that will be sent will likely be a list selection event. You need to handle this either:
in API.AI (by creating an intent with the event actions_intent_OPTION, docs here)
or
in your webhook using the Google Assistant client library (docs here).