Interface BuildCreativeError

Array of errors explaining why creative generation failed.

Per-format attribution on multi-format requests. When the request used target_format_ids[] (a batch request), sellers MUST attribute each failure to the specific format(s) that caused it so buyers can correct and retry the failing subset rather than re-running the entire batch. Two attribution surfaces, populated together:

1. error.field — set to target_format_ids[N] where N is the zero-based index of the failing format in the request's target_format_ids[] array (e.g., target_format_ids[1] for the second requested format). Mirrors the JSONPath-lite convention error.field uses elsewhere. Required when the error is format-scoped.
2. error.details.format_id — the resolved format_id value (e.g., "meta-reels-9x16"). Required when the error is format-scoped. Lets buyers dispatch on the format identity without re-parsing error.field.

Errors not attributable to a specific format (whole-batch failures: authentication, governance denial, transport-level errors) MAY omit field and details.format_id. Buyers MUST treat per-format errors as scoped to the named format only — a correctable error on target_format_ids[1] does NOT mean the buyer must reshape the entire batch; they may retry just that format with corrected input. Sellers SHOULD emit one error per failing format (rather than collapsing multiple format failures into a single error entry) so per-format recovery routing is unambiguous.