Accepting Parameters

Action functions can accept parameters, which will be parsed from the API.AI request as entities

For a parameter value to be parsed by API.AI’s NLP, it needs to relate to a defined entity. In other words, the name of the parameter must be the name of the entity it relates to.

Entities are defined:
  • using YAML templates and the schema command
  • within the API.AI console
  • as existing API.AI System Entities

Each entity is composed of entries, which represent a mapping between a reference value and a group of synonyms. Entities will be the specific value passed to the action function.

Parameters for Custom Entities

Given an entity color defined with the following template:

  - blue
  - red
  - green

An action function may accept a parameter referring to an entry (blue, red, green) of the color entity:

def echo_color(color):
    speech = "Your favorite color is {}".format(color)
    return tell(speech)

Mapping Parameters to API.AI System Entities

Every parameter passed to an action function needs to correspond to a defined entity. These entities require defined entries in order to be parsed using NLP.

With the color example above, we defined three entries (blue, red, and green). To allow our assistant to accurately parse and handle all the possible colors a user might say, we would need to provide a great number of entries.

Instead of defining many entries for common entity concepts (color, names, addresses, etc), you can utilize API.AI’s System Entities.

To use system entities, simply provide a mapping of the parameter name to corresponding system entity:

@assist.action('give-color', mapping={'color': 'sys.color'})
def echo_color(color):
    speech = "Your favorite color is {}".format(color)
    return tell(speech)

And in the user_says template:


    - My color is blue
    - I like red

    - blue: sys.color

No entity-template is needed for the sys.color entity, as it is already defined. API.AI will automatically recognize any color spoken by the user to be parsed as its sys.color entity, and flask-assistant will match the correct parameter value to the color parameter.

Prompting for Parameters

When an action function accepts a parameter, it is required unless a default is provided.

If the parameter is not provided by the user, or was not defined in a previous context, the action function will not be called.

This is where prompt_for() comes in handy.

The prompt_for decorator is passed a parameter name and intent name, and is called if the intent’s action function’s parameters have not been supplied.

@assist.prompt_for('color', intent_name='give-color')
def prompt_color(color):
    speech = "Sorry I didn't catch that. What color did you say?"
    return ask(speech)