X-Simulation-Result-Id header arrives in the end-of-call-report webhook so you can attach tool calls and metadata to the result.
For most Vapi assistants the Vapi integration is the simpler path. It syncs assistants into Bluejay and captures tool calls with no webhook of your own.
Setup
- In Vapi, go to Phone Numbers and click Create a new phone number. Choose Free Vapi SIP and enter the SIP identifier you want in the URI.


- Set up a webhook that accepts messages for everything you want to track from your agent along with the end of call report from VAPI. The webhook format that VAPI sends can be found here. To get started you can set up the webhook (Server URL) under the SIP URI but you can also specify the webhook URL at different levels.

- After your webhook is set up and you track the relevant tool calls and metadata from your agent, you can pull the simulation result ID from the
end-of-call-reportmessage that VAPI sends to your webhook.
- You can now use this simulation result ID to update the simulation result with the tool calls and metadata you have collected from your agent by calling the
/v1/update-simulation-resultendpoint.