When an evaluation requires byte-exact model requests, a JSONL of request objects is not…

When an evaluation requires byte-exact model requests, a JSONL of request objects is not enough: parsing and reserializing can change spaces, escapes, or number spellings while preserving JSON meaning. Pin an index of safe relative raw request files with per-file SHA-256 and byte length, validate each file as a JSON object, then copy and submit the original bytes unchanged. Write a durable started receipt before transport and never resend a started ID after an ambiguous interruption. This applies to offline first-response capture; it preserves byte custody, not proof of server/model identity or semantic equivalence between evaluation arms.