answering_policy_not_found
The number is visible to this tenant but carries no answering policy. Raised by GET /v1/phone-numbers/{number_id}/answering-policy and by DELETE of the same path - a delete that removed nothing says so rather than answering 204, because "already gone" and "never configured" are otherwise indistinguishable on the wire and only one of them means the caller is looking at the wrong number. Deliberately distinct from phone_number_not_found: the number exists, its document does not.
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/answering_policy_not_found",
"title": "…",
"status": 404,
"detail": "…",
"instance": "/v1/…"
}