Set values during the conversation

Amazon Lex V2 provides the ability to set slot values and session attribute values at every step of the conversation. You can then use these values during the conversation to evaluate conditions or use them during intent fulfillment.

You can set slot values for the current intent. If the next step in the conversation is to invoke another intent, you can set slot values of the new intent.

If the assigned slot is not filled, or if the JSON path cannot be parsed, then the attribute will be set to null.

Use the following syntax when using slot values and session attributes:

• Slot values – surround the slot name with braces ("{ }"). For slot values in the current intent, you only need to use the slot name. For example, {slot}. If you are setting a value in the next intent, you must use both the intent name and the slot name to identify the slot. For example, {intent.slot}.

  Examples:

  • {PhoneNumber} = "1234567890"

  • {CheckBalance.AccountNumber} = "99999999"

  • {BookingID} = "ABC123"

  • {FirstName} = "John"

  The value of a slot can be any of the following:

  • a constant string

  • a JSON path that refers to the transcriptions block in the Amazon Lex response (for en-US and en-GB)

  • a session attribute

  Examples:

  • {username} = "john.doe"

  • {username_confidence} = $.transcriptions[0].transcriptionConfidence

  • {username_slot_value} = [username]

  Note

  Slot values can also be set to null. If you need to re-elicit a slot value that has been filled, you must set the value to null before prompting the customer for the slot value again. If the assigned slot is not filled, or if the JSON path cannot be parsed, then the attribute will be set to null.

• Session attributes – surround the attribute name with square brackets ("[ ]"). For example, [sessionAttribute].

  Examples:

  • [username] = "john.doe"

  • [username_confidence] = $.transcriptions[0].transcriptionConfidence

  • [username_slot_value] = {username}

  The value of the session attribute can be any of the following:

  • a constant string

  • a JSON path that refers to the transcriptions block in the Amazon Lex response (for en-US and en-GB)

  • a slot value reference

  Note

  If the assigned slot is not filled, or if the JSON path cannot be parsed, then the attribute will be set to null.

Note

On August 17, 2022, Amazon Lex V2 released a change to the way conversations are managed with the user. This change gives you more control over the path that the user takes through the conversation. For more information, see Understanding conversation flow management. Bots created before August 17, 2022 do not support dialog code hook messages, setting values, configuring next steps, and adding conditions.