Agent Scripting API 400 on BYOC Trunk Context Injection

General Discussion
1

Just noticed that the Agent Scripting API is rejecting our custom SIP header injection attempts for BYOC trunks in the APAC region. Specifically, POST /api/v2/interaction-callbacks/agent-scripting returns a 400 Bad Request when we try to push carrier-specific routing data into the outbound dialing flow from our Singapore trunks.

The payload structure matches the documentation, but the error response indicates a schema validation failure on the customHeaders object. This is peculiar because standard Genesys Cloud trunks accept this same payload without issue. We are managing 15 BYOC trunks across multiple regions, and this failure is isolated to the Singapore endpoint.

{
 "code": "bad.request",
 "message": "The request body was not valid",
 "errors": [
 {
 "message": "Invalid structure for customHeaders in BYOC context"
 }
 ]
}

Is there a known limitation or specific configuration required for BYOC trunks to support context injection via this endpoint? We have verified the SIP credentials and outbound routing rules, which appear correct. The failover logic seems intact, but the API rejection prevents us from leveraging our carrier-specific analytics. Any insights on whether this is a regional API restriction or a configuration quirk we are missing?

2

I’d recommend looking at at the following:

  • The Agent Scripting API does not support SIP header injection, which is a common misconception when migrating from Zendesk’s custom ticket fields to GC’s telephony architecture.
  • Use the Telephony Configuration API to define custom headers in the outbound trunk settings instead of trying to inject them via interaction callbacks.
3

This is typically caused by the strict schema validation on the Agent Scripting endpoint, which does not accept custom SIP headers in the payload. Switching to the Telephony Configuration API for trunk-level header definition resolved the 400 errors in our recent BYOC deployments.