Tutorial: Building Assistants

After following the basics of setting up an assistant in the Rasa Tutorial, we’ll now walk through building a basic FAQ chatbot and then build a bot that can handle contextual conversations.

Building a simple FAQ assistant

FAQ assistants are the simplest assistants to build and a good place to get started. These assistants allow the user to ask a simple question and get a response. We’re going to build a basic FAQ assistant using features of Rasa designed specifically for this type of assistant.

In this section, we’re going to cover the following topics:

• Responding to simple intents with the MemoizationPolicy
• Handling FAQs using the ResponseSelector

You should first install Rasa using the Step-by-step Installation Guide and then follow the Rasa Tutorial to make sure you know the basics.

Memoization Policy

The MemoizationPolicy remembers examples from training stories for up to a max_history of turns. The number of “turns” includes messages the user sent, and actions the assistant performed. For the purpose of a simple, context-less FAQ bot, we only need to pay attention to the last message the user sent, and therefore we’ll set that to 1.

You can do this by editing your config.yml file as follows (you can remove TEDPolicy for now):

policies:
- name: MemoizationPolicy
  max_history: 1
- name: MappingPolicy

Now that we’ve defined our policies, we can add some stories for the goodbye, thank and greet intents to the stories.md file:

## greet
* greet
  - utter_greet

## thank
* thank
  - utter_noworries

## goodbye
* bye
  - utter_bye

Finally, we’ll copy over some NLU data from Sara into our nlu.md file:

## intent:greet
- Hi
- Hey
- Hi bot
- Hey bot
- Hello
- Good morning
- hi again
- hi folks

## intent:bye
- goodbye
- goodnight
- good bye
- good night
- see ya
- toodle-oo
- bye bye
- gotta go
- farewell

## intent:thank
- Thanks
- Thank you
- Thank you so much
- Thanks bot
- Thanks for that
- cheers

You can now train a first model and test the bot, by running the following commands:

rasa train
rasa shell

This bot should now be able to reply to the intents we defined consistently, and in any order.

For example:

While it’s good to test the bot interactively, we should also add end-to-end test cases that can later be included as part of our CI/CD system. End-to-end stories include NLU data, so that both components of Rasa can be tested. Create a file called test_stories.md in the root directory with some test cases:

## greet + goodbye
* greet: Hi!
  - utter_greet
* bye: Bye
  - utter_bye

## greet + thanks
* greet: Hello there
  - utter_greet
* thank: thanks a bunch
  - utter_noworries

## greet + thanks + goodbye
* greet: Hey
  - utter_greet
* thank: thank you
  - utter_noworries
* bye: bye bye
  - utter_bye

To test our model against the test file, run the command:

rasa test --e2e --stories test_stories.md

Response Selectors

The ResponseSelector NLU component is designed to make it easier to handle dialogue elements like Small Talk and FAQ messages in a simple manner. By using the ResponseSelector, you only need one story to handle all FAQs, instead of adding new stories every time you want to increase your bot’s scope.