The 'lex' verb connects a call to an Amazon Lex V2 bot.

{
  "verb": "lex",
  "botId": "MTLNerCD9L",
  "botAliasId": "z5yY1iYykE",
  "region": "us-east-1",
  "locale": "en_US",
  "credentials": {
    "accessKey": "XXXX",
    "secretAccessKey": "YYYY"
  },
  "passDtmf": true,
  "intent": "BookHotel",
  "metadata": {
    "slots": {
      "Location": "Los Angeles"
    },
    "context": {
      "callerId": "+15083084909",
      "customerName": "abc company"
    }
  },
  "tts": {
    "vendor": "Google",
    "language": "en-US",
    "voice": "en-US-Wavenet-C"
  }
  "eventHook": "/lex-events"
}

The following features are supported:

• optionally specify an initial, or "welcome" intent,
• pre-fill slot values for the initial intent,
• provide text for a spoken welcome message at the start of the conversation,
• play lex-generated audio, or use text-to-speech with either AWS/Polly or Google voices,
• receive real-time notifications of intents and transcriptions as the conversation progresses, and
• provide arbitrary context data to the lex backend to help guide the flow.

You can use the following options in the lex verb:

option	description	required
botId	Lex bot ID	yes
botAlias	Lex bot alias ID	yes
credentials	AWS credentials	yes
credentials.accessKey	AWS access key id	yes
credentials.secretAccessKey	AWS secret access key id	yes
region	AWS region bot is running in	yes
locale	language code of speaker (currently supported languages: en_AU, en_GB, en_US, fr_CA, fr_FR, es_ES, es_US, it_IT)	yes
eventHook	A webhook to invoke when a Lex event occurs (e.g intent detected, transcription, etc)	no
intent	initial intent to trigger (i.e. "welcome intent")	no
welcomeMessage	text for a welcome message to play to the caller	no
noInputTimeout	timeout in millseconds Lex will wait for a response before triggering fallback intent	no
tts	if provided, playback will use text-to-speech rather than Lex-generated audio	no
tts.vendor	'aws', 'Google', or 'default'	no
tts.language	language identifier or 'default'	no
tts.voice	voice identifier or 'default'	no
metadata	initial slot values and context data	no
metadata.slots	key-value pairs for slot names and initial values to be pre-filled	no
metadata.context	key-value pairs for context data to pass to Lex bot	no
metadata['x-amz-lex:channels:platform']	name of voice platform	no

The eventHook webhook will contain two parameters: event and data. The event parameter identifies the specific event and the data parameter is an object containng event data associated with the event. The following events are supported:

• intent: Lex detected an intent
• transcription: a speech transcription was returned from Lex
• response-text: Lex returned a response in the form of text
• dmtf: a dtmf key was pressed by the caller
• start-play: an audio segment returned from Lex or TTS started to play
• stop-play: an audio segment returned from Lex or TTS completing playing
• play-interrupted: an audio segment was interrupted