Action_default_fallback already defined

Fixed/hack/work-around: I don’t think this is the right approach but I got the fallback to work. I modified rasa_core.train to suport a new argument, in short:

   fallback = FallbackPolicy(core_threshold=fallback_threshold,


    agent = Agent(domain_file, policies)


    - "You are speaking nonsense my friend"

I start the training with:

python -m rasa_core.train -d domain.yml -s “$STORY” -o models/current/dialogue --epochs 120 --fallback 0.3

Edit: So I came across ´ActionDefaultFallback´ in the changelog, and found ´utter_default´ in the documentation. But when I add ´utter_default´ to my domain.yml, there still isn’t any fallback in the bot. What else do I need to set up for the default fallback to work?

I want to define a default fallback action action_default_fallback but I get the error when I run rasa_core.train

ValueError: Action names are not unique! Found two actions with name ‘action_default_fallback’. Either rename or remove one of them.

Hmm what’s the most recent edit on this? :smiley: is it working now or not? So yeah the fallback policy isn’t currently part of the train script, we’re aware of that and it should be. At the moment we just have a separate python file for the specific bot and define all the policies we want there. However, since you’ve already modified the train script – do you mind submitting a PR to Core for this?

I will clean it up and submit for a PR.

Actually looks like it was already implemented with this PR

Sorry about that, but thanks for bringing it to our attention!

Yes I noticed today as well when I did a pull. Good timing that I didn’t finish the code myself :wink:

Is the default fallback disabled by default? the vars DEFAULT_NLU_FALLBACK_THRESHOLD and DEFAULT_NLU_FALLBACK_THRESHOLD are set to 0.0. If I understood the theory behind intent classification then the probability can never be equal zero. I am tempted to set a float value myself, unless 0.0 is actually a valid value.

Yes it’s disabled by default, but you can pass the nlu/core thresholds with the --nlu_threshold and --core_threshold flags to the train script

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In action server i see action_default_fallback is triggered I0822 18:59:21.712826 139684754990912] Received request to run ‘action_default_fallback’ I0822 18:59:21.712929 139684754990912] Successfully ran ‘action_default_fallback’

But, in cmd test bot answer nothing, nevertheless i have utter_default in domain.yml and copied class ActionDefaultFallback(Action): class to

What is wrong?

You don’t actually need to copy the class to your actions file. Did you retrain your model since adding utter_default to your domain?

ERROR:rasa.core.actions.action:The model predicted the custom action ‘my_fallback_action’, but you didn’t configure an endpoint to run this custom action. Please take a look at the docs and set an endpoint configuration via the --endpoints flag. ERROR:rasa.core.processor:Encountered an exception while running action ‘my_fallback_action’. Bot will continue, but the actions events are lost. Please check the logs of your action server for more information.

I am getting this error. I have mentioned the utter_default in domain file also, but it is not calling

@karthik1 please don’t post your issue in multiple different threads, instead create a new topic and someone will get back to you there