Elasticsearch AWS S3 Snapshot Repository Authentication Error Details

Elasticsearch snapshot repositories backed by AWS S3 return a generic snapshot failed status when repository credentials expire or are misconfigured. The response omits the underlying HTTP status code and AWS error code, so the authentication root cause is not visible from the API alone. Client retry logic can transiently succeed on temporary network issues, masking a persistent credential problem.

No repository setting forces the snapshot API to return provider-specific error details, and no read-only connectivity check validates credentials without starting a snapshot. Behavior may differ across Elasticsearch releases, with newer versions potentially adding more error detail.

Can snapshot repository authentication failures be surfaced with provider-specific error codes through existing repository settings? Is there a supported read-only endpoint or repository flag to validate S3 credentials without creating a snapshot? Which Elasticsearch versions changed the snapshot error payload to include HTTP or AWS error codes?