{"abstract":"Married couples pay AMT computed with the single exemption.","category":"Tax bracket computation","checks":7,"contract":"solve(amti, regular_cents, status): stipulated AMT, whole dollars. Exemption: single 85700 (phase-out threshold 609350), mfj 133300 (threshold 1218700). The exemption is reduced by 25% of AMTI above the threshold, with the reduction rounded down to whole dollars, never below 0. Base = max(0, amti - exemption). Tentative minimum tax = 26% of base up to 232600 plus 28% of base above 232600 (in cents: dollars times percent). AMT = max(0, TMT - regular tax). Return [exemption, tmt_cents, amt_cents].","contract_signature":"amti, regular_cents, status","evaluation_group":"w2-tax_bracket_computation-alternative-minimum-tax","failed_approach":"Using the joint exemption with the single phase-out threshold still misstates high-income joint filers.","family":"w2-tax_bracket_computation-alternative-minimum-tax-status-exemption","id":"FA-62556","implementations":{"attempt":{"sha256":"e76a023429b1b35d33ae1e877a5fd8f04e18011a9cef64823e6dcbb18bb294a5","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(amti, regular_cents, status):\n    ex, thr = {'single': (85700, 609350), 'mfj': (133300, 609350)}[status]\n    if amti > thr: ex = max(0, ex - (amti - thr) // 4)\n    base = max(0, amti - ex)\n    tmt = min(base, 232600) * 26 + max(0, base - 232600) * 28\n    return [ex, tmt, max(0, tmt - regular_cents)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncases = [[('regression status-exemption 1', (1300000, 30000000, 'mfj'), [112975, 32771500, 2771500]),\n  ('regression status-exemption 2', (100000, 0, 'mfj'), [133300, 0, 0]),\n  ('partial repair guard 2', (1122405, 10000000, 'mfj'), [133300, 27229740, 17229740]),\n  ('control: moderate single', (200000, 2500000, 'single'), [85700, 2971800, 471800]),\n  ('control: partial phase-out', (700000, 0, 'single'), [63038, 17369736, 17369736]),\n  ('control: no exemption left', (1000000, 99999999, 'single'), [0, 27534800, 0]),\n  ('control: odd excess', (609353, 5000000, 'single'), [85700, 14197084, 9197084])],\n [('regression status-exemption 1', (400000, 0, 'mfj'), [133300, 7002400, 7002400]),\n  ('regression status-exemption 2', (365900, 35622995, 'mfj'), [133300, 6047600, 0]),\n  ('partial repair guard 1', (1090557, 6893581, 'mfj'), [133300, 26337996, 19444415]),\n  ('partial repair guard 2', (620628, 0, 'mfj'), [133300, 13179984, 13179984]),\n  ('control: below exemption', (100000, 0, 'mfj'), [133300, 0, 0]),\n  ('control: odd excess', (609353, 5000000, 'single'), [85700, 14197084, 9197084]),\n  ('control: joint high', (1300000, 30000000, 'mfj'), [112975, 32771500, 2771500]),\n  ('control: moderate single', (200000, 2500000, 'single'), [85700, 2971800, 471800])],\n [('regression status-exemption 1', (1122405, 10000000, 'mfj'), [133300, 27229740, 17229740]),\n  ('regression status-exemption 2', (365900, 7499416, 'mfj'), [133300, 6047600, 0]),\n  ('partial repair guard 1', (870886, 0, 'mfj'), [133300, 20187208, 20187208]),\n  ('partial repair guard 2', (697404, 2500000, 'mfj'), [133300, 15329712, 12829712]),\n  ('control: rate break', (400000, 0, 'mfj'), [133300, 7002400, 7002400]),\n  ('control: moderate single', (200000, 2500000, 'single'), [85700, 2971800, 471800]),\n  ('control: partial phase-out', (700000, 0, 'single'), [63038, 17369736, 17369736]),\n  ('control: no exemption left', (1000000, 99999999, 'single'), [0, 27534800, 0])],\n [('regression status-exemption 1', (510076, 1928999, 'mfj'), [133300, 10084528, 8155529]),\n  ('regression status-exemption 2', (318300, 22229357, 'mfj'), [133300, 4810000, 0]),\n  ('partial repair guard 1', (656646, 0, 'mfj'), [133300, 14188488, 14188488]),\n  ('partial repair guard 2', (1388032, 0, 'mfj'), [90967, 35852620, 35852620]),\n  ('control: no exemption left', (1000000, 99999999, 'single'), [0, 27534800, 0]),\n  ('control: below exemption', (100000, 0, 'mfj'), [133300, 0, 0]),\n  ('control: odd excess', (609353, 5000000, 'single'), [85700, 14197084, 9197084]),\n  ('control: joint high', (1300000, 30000000, 'mfj'), [112975, 32771500, 2771500])],\n [('regression status-exemption 1', (1090557, 6893581, 'mfj'), [133300, 26337996, 19444415]),\n  ('regression status-exemption 2', (318300, 2500000, 'mfj'), [133300, 4810000, 2310000]),\n  ('partial repair guard 1', (950664, 10000000, 'mfj'), [133300, 22420992, 12420992]),\n  ('partial repair guard 2', (716795, 0, 'mfj'), [133300, 15872660, 15872660]),\n  ('control: joint high', (1300000, 30000000, 'mfj'), [112975, 32771500, 2771500]),\n  ('control: rate break', (400000, 0, 'mfj'), [133300, 7002400, 7002400]),\n  ('control: moderate single', (200000, 2500000, 'single'), [85700, 2971800, 471800]),\n  ('control: partial phase-out', (700000, 0, 'single'), [63038, 17369736, 17369736])]]\nfor label, args, expected in cases[N - 1]:\n    check(label, solve(*args), expected)\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":"fa89615d814573ab4b435c5940b12487965ed841cce229c928c4c5d88eebdce1","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(amti, regular_cents, status):\n    ex, thr = (85700, 609350)\n    if amti > thr: ex = max(0, ex - (amti - thr) // 4)\n    base = max(0, amti - ex)\n    tmt = min(base, 232600) * 26 + max(0, base - 232600) * 28\n    return [ex, tmt, max(0, tmt - regular_cents)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncases = [[('regression status-exemption 1', (1300000, 30000000, 'mfj'), [112975, 32771500, 2771500]),\n  ('regression status-exemption 2', (100000, 0, 'mfj'), [133300, 0, 0]),\n  ('partial repair guard 2', (1122405, 10000000, 'mfj'), [133300, 27229740, 17229740]),\n  ('control: moderate single', (200000, 2500000, 'single'), [85700, 2971800, 471800]),\n  ('control: partial phase-out', (700000, 0, 'single'), [63038, 17369736, 17369736]),\n  ('control: no exemption left', (1000000, 99999999, 'single'), [0, 27534800, 0]),\n  ('control: odd excess', (609353, 5000000, 'single'), [85700, 14197084, 9197084])],\n [('regression status-exemption 1', (400000, 0, 'mfj'), [133300, 7002400, 7002400]),\n  ('regression status-exemption 2', (365900, 35622995, 'mfj'), [133300, 6047600, 0]),\n  ('partial repair guard 1', (1090557, 6893581, 'mfj'), [133300, 26337996, 19444415]),\n  ('partial repair guard 2', (620628, 0, 'mfj'), [133300, 13179984, 13179984]),\n  ('control: below exemption', (100000, 0, 'mfj'), [133300, 0, 0]),\n  ('control: odd excess', (609353, 5000000, 'single'), [85700, 14197084, 9197084]),\n  ('control: joint high', (1300000, 30000000, 'mfj'), [112975, 32771500, 2771500]),\n  ('control: moderate single', (200000, 2500000, 'single'), [85700, 2971800, 471800])],\n [('regression status-exemption 1', (1122405, 10000000, 'mfj'), [133300, 27229740, 17229740]),\n  ('regression status-exemption 2', (365900, 7499416, 'mfj'), [133300, 6047600, 0]),\n  ('partial repair guard 1', (870886, 0, 'mfj'), [133300, 20187208, 20187208]),\n  ('partial repair guard 2', (697404, 2500000, 'mfj'), [133300, 15329712, 12829712]),\n  ('control: rate break', (400000, 0, 'mfj'), [133300, 7002400, 7002400]),\n  ('control: moderate single', (200000, 2500000, 'single'), [85700, 2971800, 471800]),\n  ('control: partial phase-out', (700000, 0, 'single'), [63038, 17369736, 17369736]),\n  ('control: no exemption left', (1000000, 99999999, 'single'), [0, 27534800, 0])],\n [('regression status-exemption 1', (510076, 1928999, 'mfj'), [133300, 10084528, 8155529]),\n  ('regression status-exemption 2', (318300, 22229357, 'mfj'), [133300, 4810000, 0]),\n  ('partial repair guard 1', (656646, 0, 'mfj'), [133300, 14188488, 14188488]),\n  ('partial repair guard 2', (1388032, 0, 'mfj'), [90967, 35852620, 35852620]),\n  ('control: no exemption left', (1000000, 99999999, 'single'), [0, 27534800, 0]),\n  ('control: below exemption', (100000, 0, 'mfj'), [133300, 0, 0]),\n  ('control: odd excess', (609353, 5000000, 'single'), [85700, 14197084, 9197084]),\n  ('control: joint high', (1300000, 30000000, 'mfj'), [112975, 32771500, 2771500])],\n [('regression status-exemption 1', (1090557, 6893581, 'mfj'), [133300, 26337996, 19444415]),\n  ('regression status-exemption 2', (318300, 2500000, 'mfj'), [133300, 4810000, 2310000]),\n  ('partial repair guard 1', (950664, 10000000, 'mfj'), [133300, 22420992, 12420992]),\n  ('partial repair guard 2', (716795, 0, 'mfj'), [133300, 15872660, 15872660]),\n  ('control: joint high', (1300000, 30000000, 'mfj'), [112975, 32771500, 2771500]),\n  ('control: rate break', (400000, 0, 'mfj'), [133300, 7002400, 7002400]),\n  ('control: moderate single', (200000, 2500000, 'single'), [85700, 2971800, 471800]),\n  ('control: partial phase-out', (700000, 0, 'single'), [63038, 17369736, 17369736])]]\nfor label, args, expected in cases[N - 1]:\n    check(label, solve(*args), expected)\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":"A deterministic, bounded teaching model with a stipulated toy contract; it makes no claim of conformance to any real regulation, standard, or institution's rules. 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":"w2-tax_bracket_computation-alternative-minimum-tax-status-exemption","generated_at":"2026-09-29T14:47:05.762798+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Tax computations hinge on which slice, threshold, ordering and rounding rule applies at each step; a misplaced boundary silently misstates liabilities.","root_cause":"The exemption table ignores filing status.","sha256":"44ab2abea8573703b281483b03088eed65a381fdf897f1927da1c81b989df954","title":"Joint filers receive the single AMT exemption · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":41.322,"exit_code":1,"observations":[{"actual":[0,35934800,5934800],"check":"regression status-exemption 1","expected":[112975,32771500,2771500],"passed":false},{"actual":[133300,0,0],"check":"regression status-exemption 2","expected":[133300,0,0],"passed":true},{"actual":[5037,30821104,20821104],"check":"partial repair guard 2","expected":[133300,27229740,17229740],"passed":false},{"actual":[85700,2971800,471800],"check":"control: moderate single","expected":[85700,2971800,471800],"passed":true},{"actual":[63038,17369736,17369736],"check":"control: partial phase-out","expected":[63038,17369736,17369736],"passed":true},{"actual":[0,27534800,0],"check":"control: no exemption left","expected":[0,27534800,0],"passed":true},{"actual":[85700,14197084,9197084],"check":"control: odd excess","expected":[85700,14197084,9197084],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression status-exemption 1\", \"actual\": [0, 35934800, 5934800], \"expected\": [112975, 32771500, 2771500], \"passed\": false}, {\"check\": \"regression status-exemption 2\", \"actual\": [133300, 0, 0], \"expected\": [133300, 0, 0], \"passed\": true}, {\"check\": \"partial repair guard 2\", \"actual\": [5037, 30821104, 20821104], \"expected\": [133300, 27229740, 17229740], \"passed\": false}, {\"check\": \"control: moderate single\", \"actual\": [85700, 2971800, 471800], \"expected\": [85700, 2971800, 471800], \"passed\": true}, {\"check\": \"control: partial phase-out\", \"actual\": [63038, 17369736, 17369736], \"expected\": [63038, 17369736, 17369736], \"passed\": true}, {\"check\": \"control: no exemption left\", \"actual\": [0, 27534800, 0], \"expected\": [0, 27534800, 0], \"passed\": true}, {\"check\": \"control: odd excess\", \"actual\": [85700, 14197084, 9197084], \"expected\": [85700, 14197084, 9197084], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.427,"exit_code":1,"observations":[{"actual":[0,35934800,5934800],"check":"regression status-exemption 1","expected":[112975,32771500,2771500],"passed":false},{"actual":[85700,371800,371800],"check":"regression status-exemption 2","expected":[133300,0,0],"passed":false},{"actual":[0,30962140,20962140],"check":"partial repair guard 2","expected":[133300,27229740,17229740],"passed":false},{"actual":[85700,2971800,471800],"check":"control: moderate single","expected":[85700,2971800,471800],"passed":true},{"actual":[63038,17369736,17369736],"check":"control: partial phase-out","expected":[63038,17369736,17369736],"passed":true},{"actual":[0,27534800,0],"check":"control: no exemption left","expected":[0,27534800,0],"passed":true},{"actual":[85700,14197084,9197084],"check":"control: odd excess","expected":[85700,14197084,9197084],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression status-exemption 1\", \"actual\": [0, 35934800, 5934800], \"expected\": [112975, 32771500, 2771500], \"passed\": false}, {\"check\": \"regression status-exemption 2\", \"actual\": [85700, 371800, 371800], \"expected\": [133300, 0, 0], \"passed\": false}, {\"check\": \"partial repair guard 2\", \"actual\": [0, 30962140, 20962140], \"expected\": [133300, 27229740, 17229740], \"passed\": false}, {\"check\": \"control: moderate single\", \"actual\": [85700, 2971800, 471800], \"expected\": [85700, 2971800, 471800], \"passed\": true}, {\"check\": \"control: partial phase-out\", \"actual\": [63038, 17369736, 17369736], \"expected\": [63038, 17369736, 17369736], \"passed\": true}, {\"check\": \"control: no exemption left\", \"actual\": [0, 27534800, 0], \"expected\": [0, 27534800, 0], \"passed\": true}, {\"check\": \"control: odd excess\", \"actual\": [85700, 14197084, 9197084], \"expected\": [85700, 14197084, 9197084], \"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."}}