google_signin_unavailable
POST /v1/auth/google in a deployment with no VOCAPABLE_GOOGLE_SIGNIN_CLIENT_ID configured. The surface is unavailable, not open - the portal discovers this through GET /v1/auth/providers and shows no button.
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/google_signin_unavailable",
"title": "…",
"status": 503,
"detail": "…",
"instance": "/v1/…"
}