{"run_id":"challenge_challenge_run_meridian_003_claude-haiku-4-5-20251001_2_claude-opus-4-6","chain_valid":true,"first_broken_seq":null,"chain_head":"7c5bf815fdd25fde508e272726152eb3735e710b9770aa48d4ea7eab11da4836","event_count":4,"genesis_ts":"2026-06-14T05:02:52.313303+00:00","model_snapshot":"claude-opus-4-6","fault_count":1,"merkle_root":"65988226cec31caaaacbbfbceba476105ee2be03b4caab4f34eaa081fc5e56ee","anchor_date":"2026-06-14","verification_algorithm":"sha256-chain","verification_spec":"hash = sha256(prev_hash + canonical_json(event_fields))","computed_at":"2026-06-18T07:32:24.076404+00:00"}