{"abstract":"Causal position does not reset at segment boundaries.","category":"Attention mask construction","checks":6,"contract":"Each entry is [segment_id, local_position]; visible iff IDs match and key local position<=query local position.","contract_signature":"segments","evaluation_group":"segmented_causal_reset_v1","failed_approach":"Resetting at segment start but ignoring segment labels permits another segment with the same local position.","family":"w3-attention-mask-construction-segment-reset-causal","id":"FA-98201","implementations":{"attempt":{"sha256":"b122c3a9ee3cc8f748fded585694e0a6ed172bff1ae0b003fe3f5e282467e347","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(segments):\n    return [[segments[j][1]<=segments[i][1] for j in range(len(segments))] for i in range(len(segments))]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ns=[[0,i] for i in range(N)]+[[1,0],[1,1]]\ncheck('reset and isolate',solve(s),[[s[j][0]==s[i][0] and s[j][1]<=s[i][1] for j in range(len(s))] for i in range(len(s))])\ncheck('one segment',solve([[4,0],[4,1]]),[[True,False],[True,True]])\ncheck('same local index different segment',solve([[1,0],[2,0]]),[[True,False],[False,True]])\ncheck('empty',solve([]),[])\ncheck('singleton',solve([[3,7]]),[[True]])\ncheck('local order differs global',solve([[5,1],[5,4]]),[[True,False],[True,True]])\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":"5ed60c5c6d000ea06ff015eb261dd1d3555fab36aa297c3487df74842429a9d5","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(segments):\n    return [[j<=i for j in range(len(segments))] for i in range(len(segments))]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ns=[[0,i] for i in range(N)]+[[1,0],[1,1]]\ncheck('reset and isolate',solve(s),[[s[j][0]==s[i][0] and s[j][1]<=s[i][1] for j in range(len(s))] for i in range(len(s))])\ncheck('one segment',solve([[4,0],[4,1]]),[[True,False],[True,True]])\ncheck('same local index different segment',solve([[1,0],[2,0]]),[[True,False],[False,True]])\ncheck('empty',solve([]),[])\ncheck('singleton',solve([[3,7]]),[[True]])\ncheck('local order differs global',solve([[5,1],[5,4]]),[[True,False],[True,True]])\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":"These are toy Boolean matrix contracts; they do not define a production model architecture or tensor library behavior. 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":"w3-attention-mask-construction-segment-reset-causal","generated_at":"2026-09-30T16:48:10.629822+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A small explicit visibility matrix makes sequence-attention boundary behavior reviewable.","root_cause":"Absolute flattened index controls causality across separately indexed segments.","sha256":"3199df36c851be76c94a10fc2afe6fb9a7e0cc0883a8fb3d149cb826a0c47048","title":"Causal position does not reset at segment boundaries · case 01","variant":1,"variant_policy":"The fixture code references N, supplied as 1 through 5. Fixed boundary checks may repeat. These records share one mechanism and must remain together in evaluation splits.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":28.558,"exit_code":1,"observations":[{"actual":[[true,true,false],[true,true,false],[true,true,true]],"check":"reset and isolate","expected":[[true,false,false],[false,true,false],[false,true,true]],"passed":false},{"actual":[[true,false],[true,true]],"check":"one segment","expected":[[true,false],[true,true]],"passed":true},{"actual":[[true,true],[true,true]],"check":"same local index different segment","expected":[[true,false],[false,true]],"passed":false},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[[true]],"check":"singleton","expected":[[true]],"passed":true},{"actual":[[true,false],[true,true]],"check":"local order differs global","expected":[[true,false],[true,true]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"reset and isolate\", \"actual\": [[true, true, false], [true, true, false], [true, true, true]], \"expected\": [[true, false, false], [false, true, false], [false, true, true]], \"passed\": false}, {\"check\": \"one segment\", \"actual\": [[true, false], [true, true]], \"expected\": [[true, false], [true, true]], \"passed\": true}, {\"check\": \"same local index different segment\", \"actual\": [[true, true], [true, true]], \"expected\": [[true, false], [false, true]], \"passed\": false}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"singleton\", \"actual\": [[true]], \"expected\": [[true]], \"passed\": true}, {\"check\": \"local order differs global\", \"actual\": [[true, false], [true, true]], \"expected\": [[true, false], [true, true]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":28.983,"exit_code":1,"observations":[{"actual":[[true,false,false],[true,true,false],[true,true,true]],"check":"reset and isolate","expected":[[true,false,false],[false,true,false],[false,true,true]],"passed":false},{"actual":[[true,false],[true,true]],"check":"one segment","expected":[[true,false],[true,true]],"passed":true},{"actual":[[true,false],[true,true]],"check":"same local index different segment","expected":[[true,false],[false,true]],"passed":false},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[[true]],"check":"singleton","expected":[[true]],"passed":true},{"actual":[[true,false],[true,true]],"check":"local order differs global","expected":[[true,false],[true,true]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"reset and isolate\", \"actual\": [[true, false, false], [true, true, false], [true, true, true]], \"expected\": [[true, false, false], [false, true, false], [false, true, true]], \"passed\": false}, {\"check\": \"one segment\", \"actual\": [[true, false], [true, true]], \"expected\": [[true, false], [true, true]], \"passed\": true}, {\"check\": \"same local index different segment\", \"actual\": [[true, false], [true, true]], \"expected\": [[true, false], [false, true]], \"passed\": false}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"singleton\", \"actual\": [[true]], \"expected\": [[true]], \"passed\": true}, {\"check\": \"local order differs global\", \"actual\": [[true, false], [true, true]], \"expected\": [[true, false], [true, true]], \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}