Dean,
I think the challenge is that the callout to the lambda is a function of your Lex bot itself, when a particular intent is recognized and a slot is triggered from the intent the lambda is called. All of this happens outside of the visibility of PureCloud invocation of the Lex bot. I'm also not sure that PureCloud is setup to process the SSML response supported by the Lambda (someone else is going to need to respond to this point). Lambdas that are invoked and return back a text response as the slot output SHOULD behave as normal within the call flow.
A very near term alternative to this is to invoke the lambda directly from the PureCloud call flow. In the next couple weeks we will be releasing support for invoking lambdas directly as custom data actions (similar to Salesforce/Zendesk/MSDynamics/Web Service Data Actions). This will allow the intents and slots to processed within your call flow as they currently are, then invoke the lambda as a data action to achieve the same basic end result.
Lambda data action support will be announced through the PureCloud platform release notes and will be available to all PureCloud 1, 2, and 3 orgs.
Let me know if there's additional questions on this.
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Richard Schott
Genesys - Employees
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