{"abstract":"A mixed-endian identifier reverses every field.","category":"Binary formats","checks":4,"contract":"For 16 bytes, reverse the first 4-byte field and following two 2-byte fields; retain final 8 bytes. Return hex.","evaluation_group":"model-e0879594be23f65f","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-binary-mixed-endian-guid","id":"FA-3741","implementations":{"attempt":{"sha256":"105e6dffa7e8e93d355a20f96be45e1ddd3bc1709fe74806b425fcc8dd6f26f9","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct\nfrom urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit\nfrom email.header import decode_header, make_header\nfrom email.utils import getaddresses\nfrom xml.etree import ElementTree as ET\nimport shlex, string, textwrap\n\nN = 1\nobservations = []\ndef solve(x):\n    try:\n        return bytes(reversed(x)).hex()\n    except Exception as exc:\n        return {\"error\": type(exc).__name__}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('boundary 1', solve([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]), '030201000504070608090a0b0c0d0e0f')\ncheck('boundary 2', solve([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]), '00000000000000000000000000000000')\ncheck('boundary 3', solve([1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]), '01010101010101010101010101010101')\ncheck('boundary 4', solve([0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]), '00000100000000000000000000000000')\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"898eb24a66eb02b3ce5957fe369c87ebac4873b582713bc5ef3e8627ca301125","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct\nfrom urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit\nfrom email.header import decode_header, make_header\nfrom email.utils import getaddresses\nfrom xml.etree import ElementTree as ET\nimport shlex, string, textwrap\n\nN = 1\nobservations = []\ndef solve(x):\n    try:\n        return bytes(x).hex()\n    except Exception as exc:\n        return {\"error\": type(exc).__name__}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('boundary 1', solve([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]), '030201000504070608090a0b0c0d0e0f')\ncheck('boundary 2', solve([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]), '00000000000000000000000000000000')\ncheck('boundary 3', solve([1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]), '01010101010101010101010101010101')\ncheck('boundary 4', solve([0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]), '00000100000000000000000000000000')\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"eb2ddf1e739b0fb80470f6a145b88b5003f18e7cbfb9732a291006b5d9915641","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct\nfrom urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit\nfrom email.header import decode_header, make_header\nfrom email.utils import getaddresses\nfrom xml.etree import ElementTree as ET\nimport shlex, string, textwrap\n\nN = 1\nobservations = []\ndef solve(x):\n    try:\n        return bytes(x[:4][::-1]+x[4:6][::-1]+x[6:8][::-1]+x[8:]).hex()\n    except Exception as exc:\n        return {\"error\": type(exc).__name__}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('boundary 1', solve([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]), '030201000504070608090a0b0c0d0e0f')\ncheck('boundary 2', solve([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]), '00000000000000000000000000000000')\ncheck('boundary 3', solve([1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]), '01010101010101010101010101010101')\ncheck('boundary 4', solve([0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]), '00000100000000000000000000000000')\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":" This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"xp-binary-mixed-endian-guid","generated_at":"2026-09-29T14:37:30.223969+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A local executable model for consumers of structured text; oracle values are authored literals, not outputs copied from the repaired implementation.","repair":"Implement the complete stated contract, including the boundary fixtures: For 16 bytes, reverse the first 4-byte field and following two 2-byte fields; retain final 8 bytes. Return hex.","root_cause":"The implementation applies an operation whose text or grammar semantics violate this contract: For 16 bytes, reverse the first 4-byte field and following two 2-byte fields; retain final 8 bytes. Return hex.","sha256":"341185450044d89c6285ec1d529a935e5cd0153effd71ba2326e192dbeb0d081","title":"A mixed-endian identifier reverses every field · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":49.324,"exit_code":1,"observations":[{"actual":"0f0e0d0c0b0a09080706050403020100","check":"boundary 1","expected":"030201000504070608090a0b0c0d0e0f","passed":false},{"actual":"00000000000000000000000000000000","check":"boundary 2","expected":"00000000000000000000000000000000","passed":true},{"actual":"01010101010101010101010101010101","check":"boundary 3","expected":"01010101010101010101010101010101","passed":true},{"actual":"00000000000000000000000000000100","check":"boundary 4","expected":"00000100000000000000000000000000","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"0f0e0d0c0b0a09080706050403020100\", \"expected\": \"030201000504070608090a0b0c0d0e0f\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"00000000000000000000000000000000\", \"expected\": \"00000000000000000000000000000000\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"01010101010101010101010101010101\", \"expected\": \"01010101010101010101010101010101\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"00000000000000000000000000000100\", \"expected\": \"00000100000000000000000000000000\", \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":52.521,"exit_code":1,"observations":[{"actual":"000102030405060708090a0b0c0d0e0f","check":"boundary 1","expected":"030201000504070608090a0b0c0d0e0f","passed":false},{"actual":"00000000000000000000000000000000","check":"boundary 2","expected":"00000000000000000000000000000000","passed":true},{"actual":"01010101010101010101010101010101","check":"boundary 3","expected":"01010101010101010101010101010101","passed":true},{"actual":"00010000000000000000000000000000","check":"boundary 4","expected":"00000100000000000000000000000000","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"000102030405060708090a0b0c0d0e0f\", \"expected\": \"030201000504070608090a0b0c0d0e0f\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"00000000000000000000000000000000\", \"expected\": \"00000000000000000000000000000000\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"01010101010101010101010101010101\", \"expected\": \"01010101010101010101010101010101\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"00010000000000000000000000000000\", \"expected\": \"00000100000000000000000000000000\", \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":55.206,"exit_code":0,"observations":[{"actual":"030201000504070608090a0b0c0d0e0f","check":"boundary 1","expected":"030201000504070608090a0b0c0d0e0f","passed":true},{"actual":"00000000000000000000000000000000","check":"boundary 2","expected":"00000000000000000000000000000000","passed":true},{"actual":"01010101010101010101010101010101","check":"boundary 3","expected":"01010101010101010101010101010101","passed":true},{"actual":"00000100000000000000000000000000","check":"boundary 4","expected":"00000100000000000000000000000000","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"030201000504070608090a0b0c0d0e0f\", \"expected\": \"030201000504070608090a0b0c0d0e0f\", \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": \"00000000000000000000000000000000\", \"expected\": \"00000000000000000000000000000000\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"01010101010101010101010101010101\", \"expected\": \"01010101010101010101010101010101\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"00000100000000000000000000000000\", \"expected\": \"00000100000000000000000000000000\", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}