outbound_caller_id_required
An ad-hoc live call's verified default BYO account has no active, tenant-assigned, carrier-confirmed voice number. The request cannot name a caller ID; configure one on the account and retry.
Problem shape
Every non-2xx response is an RFC 9457 application/problem+json body. The type URI below is stable and machine-matchable, so branch on the final path segment (the code) and treat the status as redundant confirmation. See the error-handling guide.
{
"type": "https://docs.vocapable.com/errors/outbound_caller_id_required",
"title": "…",
"status": 409,
"detail": "…",
"instance": "/v1/…"
}