Actions

Actions

Actions are the things your bot runs in response to user input. There are four kinds of actions in Rasa:

  1. Utterance actions: start with utter_ and send a specific message to the user.
  2. Retrieval actions: start with respond_ and send a message selected by a retrieval model.
  3. Custom actions: run arbitrary code and send any number of messages (or none).
  4. Default actions: e.g. action_listen, action_restart, action_default_fallback.

Utterance Actions

To define an utterance action (ActionUtterTemplate), add a response to the domain file that starts with utter_:

responses:
  utter_my_message:
    - "this is what I want my action to say!"

It is conventional to start the name of an utterance action with utter_. If this prefix is missing, you can still use the response in your custom actions, but the response can not be directly predicted as its own action. See Responses for more details.

If you use an external NLG service, you don’t need to specify the responses in the domain, but you still need to add the utterance names to the actions list of the domain.

Retrieval Actions

Retrieval actions make it easier to work with a large number of similar intents like chitchat and FAQs. See Retrieval Actions to learn more.

Custom Actions

An action can run any code you want. Custom actions can turn on the lights, add an event to a calendar, check a user’s bank balance, or anything else you can imagine.

Rasa will call an endpoint you can specify, when a custom action is predicted. This endpoint should be a webserver that reacts to this call, runs the code and optionally returns information to modify the dialogue state.

To specify, your action server use the endpoints.yml:

action_endpoint:
  url: "http://localhost:5055/webhook"

And pass it to the scripts using --endpoints endpoints.yml.

You can create an action server in node.js, .NET, java, or any other language and define your actions there - but we provide a small python SDK to make development there even easier.

Custom Actions Written in Python

For actions written in python, we have a convenient Rasa SDK which starts this action server for you.

Execute Actions in Other Code

Rasa will send an HTTP POST request to your server containing information on which action to run. Furthermore, this request will contain all information about the conversation. Action Server shows the detailed API spec.

As a response to the action call from Rasa, you can modify the tracker, e.g. by setting slots and sending responses back to the user. All of the modifications are done using events. There is a list of all possible event types in Events.

Default Actions

The available default actions are:

Action Name Description
action_listen Stop predicting more actions and wait for user input.
action_restart Reset the whole conversation. Can be triggered during a conversation by entering /restart.
action_session_start Start a new conversation session.
action_default_fallback Undo the last user message and utter a message that the bot did not understand.
action_deactivate_form Deactivate the active form and reset the requested slot.
action_revert_fallback_events Revert events that occurred during the TwoStageFallbackPolicy.
action_default_ask_affirmation Ask the user to affirm their intent.
action_default_ask_rephrase Ask the user to rephrase their intent.
action_back Undo the last user message.

All the default actions can be overridden. To do so, add the action name to the list of actions in your domain:

actions:
- action_default_ask_affirmation

Rasa will then call your action endpoint and treat it as every other custom action.