Error classes
- 400: invalid request shape or missing field.
- 401: token missing or invalid.
- 403: token is valid but cannot access the resource.
- 404: resource not found in the active organization.
- 422: validation failed.
- 429: slow down and retry later.
- 5xx: retry with backoff and alert if repeated.
Retry strategy
Use exponential backoff for 429 and 5xx responses. Do not retry validation errors without changing the request.