While implementing and reviewing XEP-0171 (Language Translation), I noticed that the specification currently lacks an explicit standard error response for scenarios where the translation service is busy, overloaded, or rate-limiting requests (e.g., hitting quota limits or temporary server congestion). According to RFC 6120, the `<resource-constraint/>` defined-condition with error type `wait` indicates that the entity lacks the system resources (CPU, memory, quotas, etc.) necessary to service the stanza, which fits this use case perfectly: ``` <iq type='error' id='translationReq' from='translation.robot.com' to='ace@example.com'> <error type='wait'> <resource-constraint xmlns='urn:ietf:xml:params:ns:xmpp-stanzas'/> </error> </iq> ``` (Note: depending on implementation, an optional application-specific error element or human-readable <text/> could accompany it if needed). Explicitly documenting this would improve interoperability and guide client developers on how to implement retry logic or display appropriate feedback to users, rather than treating rate-limiting as a generic/permanent failure.