Execute only action_default_ask_rephrase in Two Stage Fallback Plicy

Rasa Open Source
1

I am using Two-Stage-Fallback policy. However, my requirement is to just ask the user to ‘Rephrase’ rather than asking the user to confirm the intent ie I want to just execute action_default_ask_rephrase. I do not want to execute : action_default_ask_affirmation

User: I need to install software

Bot: I did not understand. Could you rephrase

User: I need to install rasa on my server

Bot: (If intent recognition happens / policies predict the action) Do xyz… (If not) Sorry I will route your query

Any help is much appreciated.

2

I think a simple Custom Fallback is more suitable to your requirements. Inside the custom action, you can get the older events with reversed(tracker.events[:-1]) and check if there was a previous fallback. If there was not, just utter_message asking to rephrase and return UserUtteranceReverted. If there was, you can route right there or return a FollowupAction.

3

Hi, I am trying what you just suggested. How can we check for a previous fallback with reversed(tracker.events[:-1]) ? When I check for that value I just see <list_reverseiterator object at 0x7fcffe4b2a90>

Sorry if I am missing something

4

No problem. Try to call a method from your custom fallback to check if the user is in a second fallback (consecutive or not). In your method, place something like:

for event in reversed(tracker.events[:-1]):
    
    if event.get('event') == 'action' and event.get('name') == 'action_custom_fallback':                  
        return True

return False
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5

Hi, this is great. For my requirement, I need ask the user to rephrase if the user enters the fallback action in second conversation. For instance: This is the expected flow: User: I need to install software

Bot: I did not understand. Could you rephrase

User: I need to install rasa on my server

Bot: (If intent recognition happens / policies predict the action) Do xyz… (If not) Sorry I will route your query

User: I need to book a flight

Bot: Please rephrase

User: I need a flight to London

Bot: (If intent recognition happens / policies predict the action) Do xyz… (If not) Sorry I will route your query

But because the tracker.events has fallback policy previously, second time when ‘I need to book a flight’ instead of asking to rephrase the bot is directly routing it right there.

I did try to clear the list of tracker.events after every fallback policy. That does not work. Any help on this can be tackled?

6

Well, you can limit the routing behavior to consecutive fallbacks only. That is, “Sorry I will route your query” will only happen when the previous action was also a fallback, otherwise ask to rephrase.

When speaking we say previous, but the tracker has a lot of info between what the user sees, like action_listen. Take a look on how your conversation history is being saved, and try to identify what it looks like when you have two consecutive fallbacks. Then you will change the code I sent to catch this condition to route the query.

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