Errors and notes

• Errors: 401 invalid or missing key, 403 project not on this key, 422 invalid config or items missing a required field, 503 service unavailable.
• Idempotency: send an Idempotency-Key header per batch so retries are safe. Without one, each /ingest appends its items.
• Content shape is up to you as long as it matches the configured task. For text review, typically prompt plus output. Add case_id to tie results back to your records.