So I have been trying to figure this out for the last few days and need some help. I am creating an appointment setting system between vapi and make. All is good except Vapie is not receiving the information. I have 2 approaches which I have documented in the attachments. Approach 1 ideal - uses the time before the caller get connected to the agent to get information from make. I get variables passed back to vapi but since the list of available times takes longer I have a seperate webhook response which is not working. Approach 2 - Typical toolcall from vapi to make. It seems simple however for some reason it is not working. I have uploaded areas where I think the problems in the set up could be, Phone, assistant, tool. Also included few pics of the 2 approaches what i have tried and some sample responses and webhook settings. Any guidance would be appreciated!! https://cdn.discordapp.com/attachments/1416845211190952087/1416845211686015147/Webhook_Response_1_-_Approach2_-_Variable_Response_Code.txt?ex=68c8536e&is=68c701ee&hm=aa379dabd76f27ccd57a7a5bf756985b305c993e7840e260e0356dc3b3791358& https://cdn.discordapp.com/attachments/1416845211190952087/1416845212168486934/Webhook_Response_1_-_Approach2_-_Variable_Response.txt?ex=68c8536e&is=68c701ee&hm=2067553e136c44a83d5c4072f48ea987cbc16746898a3efa996ea845d3a64839& https://cdn.discordapp.com/attachments/1416845211190952087/1416845212701032622/Webhook_Response_V1-_Variable_Response_code.txt?ex=68c8536e&is=68c701ee&hm=41b18e079a71b643c2bef9146fc13a4da360cc2d146469deabc1f50e941542cf& https://cdn.discordapp.com/attachments/1416845211190952087/1416845213325857002/Webhook_Response_V1-_Variable_output.txt?ex=68c8536e&is=68c701ee&hm=471ff8985e8e4382f9853c8a1267d87dc501f2309d57e58372dbdf7b269bd1d8& https://cdn.discordapp.com/attachments/1416845211190952087/1416845214106259487/Phone_Number_Settings_1.jpg?ex=68c8536e&is=68c701ee&hm=a48e5fbfeb68f6df047aca9fa4557623e4799f44ca769f6aef1814b85d1a63de& https://cdn.discordapp.com/attachments/1416845211190952087/1416845214601052311/Approach_2-_Availability_Tool.jpg?ex=68c8536e&is=68c701ee&hm=8fc5b16db146d213342a12ec0edd600f2efa3dcfa67c494d642268865d583552& https://cdn.discordapp.com/attachments/1416845211190952087/1416845215221813390/Approach_1-_Contact_Lookup.jpg?ex=68c8536f&is=68c701ef&hm=44efba3d8e2e7840329e264376289e6b72dcf35a2ca127dc87a6a064a87d3cbc& https://cdn.discordapp.com/attachments/1416845211190952087/1416845215725125762/Assistant_-_Setup_1.json?ex=68c8536f&is=68c701ef&hm=ad2afcbc06759a40704eb97cfb89983b8fa187f09a7131e118c295f6a1a4791e& https://cdn.discordapp.com/attachments/1416845211190952087/1416845216241029291/checkAvailability_-_Tool.txt?ex=68c8536f&is=68c701ef&hm=e3e810e1b70bbbad8a7438ceee3649a4995142270c5d9c41faa981715da9d2e5&

I can help identify why your Vapi–Make integration isn’t passing data correctly and get your appointment system working smoothly. From what you’ve shared, it looks like the core issues could be: the assistant not being assigned to the inbound phone number, a mismatch between your JSON responses and what Vapi expects, and potential data type or field name inconsistencies in your tool calls and webhook responses. I can review your webhook responses, tool call definitions, and assistant configuration to ensure Vapi can properly ingest the data. We can also simplify and test your responses step by step to isolate the exact point of failure and avoid delays for callers. Quick question: have you already verified that the assistant is assigned to the number and that the variable names in your JSON exactly match Vapi’s expected schema? @Noid

Great thought. However what I learned, to get the variables before the caller connects to the agent the assistant should be left blank on the phone number. The assistant is a hybrid mode between transient and permanent mode. I did not know any other way to get the variables during the precall time.

That clarify the precall setup, leaving the assistant blank makes sense for capturing variables early. I’ve worked with similar Vapi setups and can assist in troubleshooting the webhook and tool call issues, including JSON structure and variable handling. I can assist step by step to test the flows and ensure data is reliably passed before the caller connects. If you like, we can continue this privately or on a call to get it working smoothly.

Oh that would be great and much appreciated. What way works best for you to connect ?

Perfect, glad to hear that. The easiest way for us to connect is on WhatsApp—here’s my number: +2348141449023. Feel free to message me there and we can continue the conversation in detail

For "Webhook Response 1 - Approach2", the problem is that you need to render the array as a JSON string, rather than sending the Make object. Take a look at using the "Aggregate to JSON" module rather than a simple Aggregator. For "Webhook Response V1", the problem is that your OpenAI module is sending

'''json

along with the JSON body. To solve this, open up the `Advanced `section in that module and set the `Type `of the

Output Format

to be

JSON object

. If you need other help on Make scenarios with Vapi, you'd be best posting the Make Community at https://community.make.com

We are looking into this some more and will provide an update shortly