Hi, I am new to VAPI and trying to find CURRENT (as of June 2025), AUTHORITATIVE DOCUMENTATION on the required output formats for API calls and Tools. I am trying to get a dead simple use case of returning a first name, last name and user id from an API call and being able to have VAPI speak and save their name and save their id for a future call. I had success in an Attendant but ran into issues with logic, now the Workflow looks like the ideal approach o handle logic, but I couldn't get the same Tool to get invoked at all from Workflow, and while an API call is working, I have seen documentation that says that you can ONLY return simple strings, and other docs that say you can return JSON objects. Can someone point me to a 100% WORKING EXAMPLE of: 1. Calling an API or Tool from Workflow 2. The EXACT SYNTAX for a successful response 3. EXACTLY how to tell VAPI how to read, save and speak elements in the response. I am using the VAPI API and JSON payloads to manage my workflows.