Custom slot type

For each intent, you can specify parameters that indicate the information that the intent needs to fulfill the user's request. These parameters, or slots, have a type. A slot type is a list of values that Amazon Lex V2 uses to train the machine learning model to recognize values for a slot. For example, you can define a slot type called Genres with values such as "comedy," "adventure," "documentary," etc. You can define synonyms for a slot type value. For example, you can define the synonyms "funny" and "humorous" for the value "comedy."

You can configure the slot type to expand the slot values. Slot values will be used as training data and the model will resolve the slot to the value provided by the user if it is similar to the slot values and synonyms of those values. This is the default behavior. Amazon Lex V2 maintains a list of possible resolutions for a slot. Each entry in the list provides a resolved value that Amazon Lex V2 recognized as additional possibilities for the slot. A resolved value is the best effort to match the slot value. The list contains up to five values.

Alternatively, you can configure the slot type to restrict resolution to the slot values. In this case, the model will resolve a slot value entered by the user to an existing slot value only if it is the same as that slot value or it is a synonym. For example, if the user enters "funny" it will resolve to the slot value "comedy."

When the value entered by the user is a synonym of a slot type value, the model returns that slot type value as the first entry in the list of resolvedValues. For example, if the user enters "funny," the model populates the originalValue field with the value "funny" and the first entry in the resolvedValues field with "comedy." You can configure the valueSelectionStrategy when you create or update a slot type with the CreateSlotType operation so that the slot value is filled with the first value in the resolution list.

Custom slot types support inputs using spelling styles. You can use the spell-by-letter and spell-by-word styles to help your customers enter letters. For more information, see Capturing slot values with spelling styles during the conversation.

If you are using a Lambda function, the input event to the function includes a resolution list called resolvedValues. The following example shows the slot section of the input to a Lambda function:

   "slots": {
      "MovieGenre": {
         "value": {
            "originalValue": "funny",
            "interpretedValue": "comedy",
            "resolvedValues": [
               "comedy"
            ]
         }
      }
   }

For each slot type, you can define a maximum of 10,000 values and synonyms. Each bot can have a total number of 50,000 slot type values and synonyms. For example, you can have 5 slot types, each with 5,000 values and 5,000 synonyms, or you can have 10 slot types, each with 2,500 values and 2,500 synonyms.

A custom slot type should not have the same name as the built-in slot types. For example, a custom slot type should not be named with the reserved keywords of Date, Number, or Confirmation. These keywords are reserved for built-in slot types. For a list of all built-in slot types, see Built-in slot types.