{"abstract":"Filers entitled to a refund receive zero.","category":"Tax bracket computation","checks":6,"contract":"solve(state, nonref, ref, pct): amounts in integer cents; pct a decimal percentage string. State tax after nonrefundable credits is max(0, state - nonref). The local surtax is pct% of that amount, rounded half-up to cents. Refundable credits then apply to the combined total in full (a negative total is a refund). Return [local, total].","evaluation_group":"w2-tax_bracket_computation-local-piggyback-surtax","failed_approach":"Letting refundable credits offset only the state portion still denies refunds against the surtax.","family":"w2-tax_bracket_computation-local-piggyback-surtax-refundable-order","id":"FA-62701","implementations":{"attempt":{"sha256":"ddcfafbac2640bd9f0fccaf6dc86fe06b0cfbfd569607f59830ff99329a74182","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom fractions import Fraction\nN = 1\nobservations = []\ndef solve(state, nonref, ref, pct):\n    after = max(0, state - nonref)\n    local = int(after * Fraction(pct) / 100 + Fraction(1, 2))\n    return [local, max(0, after - ref) + local]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncases = [[('regression refundable-order 1', (5000, 1000, 9000, '12.5'), [500, -4500]),\n  ('regression refundable-order 2', (1000, 3000, 500, '20'), [0, -500]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000]),\n  ('control: rounding', (333, 0, 0, '1.5'), [5, 338]), ('control: half cent', (1001, 0, 0, '50'), [501, 1502]),\n  ('control: no surtax', (4200, 100, 0, '0'), [0, 4100])],\n [('regression refundable-order 1', (18157, 72365, 10702, '3.25'), [0, -10702]),\n  ('regression refundable-order 2', (60634, 89812, 9000, '12.5'), [0, -9000]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500]),\n  ('control: half cent', (1001, 0, 0, '50'), [501, 1502]), ('control: no surtax', (4200, 100, 0, '0'), [0, 4100]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000])],\n [('regression refundable-order 1', (7099, 20000, 500, '20'), [0, -500]),\n  ('regression refundable-order 2', (27020, 20000, 9000, '3.25'), [228, -1752]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000]),\n  ('control: credits exceed tax', (1000, 3000, 500, '20'), [0, -500]),\n  ('control: rounding', (333, 0, 0, '1.5'), [5, 338]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500])],\n [('regression refundable-order 1', (4316, 0, 9000, '17.5'), [755, -3929]),\n  ('regression refundable-order 2', (63135, 85065, 500, '20'), [0, -500]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500]),\n  ('control: half cent', (1001, 0, 0, '50'), [501, 1502]), ('control: no surtax', (4200, 100, 0, '0'), [0, 4100]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000])],\n [('regression refundable-order 1', (5225, 20000, 9000, '8'), [0, -9000]),\n  ('regression refundable-order 2', (18855, 20000, 500, '50'), [0, -500]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000]),\n  ('control: credits exceed tax', (1000, 3000, 500, '20'), [0, -500]),\n  ('control: rounding', (333, 0, 0, '1.5'), [5, 338]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500])]]\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":"d2cd39bd4acab32fb9a4dceb801a6c9a58dcb5d27222a5f116daec0b05339f50","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom fractions import Fraction\nN = 1\nobservations = []\ndef solve(state, nonref, ref, pct):\n    after = max(0, state - nonref)\n    local = int(after * Fraction(pct) / 100 + Fraction(1, 2))\n    return [local, max(0, after + local - ref)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncases = [[('regression refundable-order 1', (5000, 1000, 9000, '12.5'), [500, -4500]),\n  ('regression refundable-order 2', (1000, 3000, 500, '20'), [0, -500]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000]),\n  ('control: rounding', (333, 0, 0, '1.5'), [5, 338]), ('control: half cent', (1001, 0, 0, '50'), [501, 1502]),\n  ('control: no surtax', (4200, 100, 0, '0'), [0, 4100])],\n [('regression refundable-order 1', (18157, 72365, 10702, '3.25'), [0, -10702]),\n  ('regression refundable-order 2', (60634, 89812, 9000, '12.5'), [0, -9000]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500]),\n  ('control: half cent', (1001, 0, 0, '50'), [501, 1502]), ('control: no surtax', (4200, 100, 0, '0'), [0, 4100]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000])],\n [('regression refundable-order 1', (7099, 20000, 500, '20'), [0, -500]),\n  ('regression refundable-order 2', (27020, 20000, 9000, '3.25'), [228, -1752]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000]),\n  ('control: credits exceed tax', (1000, 3000, 500, '20'), [0, -500]),\n  ('control: rounding', (333, 0, 0, '1.5'), [5, 338]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500])],\n [('regression refundable-order 1', (4316, 0, 9000, '17.5'), [755, -3929]),\n  ('regression refundable-order 2', (63135, 85065, 500, '20'), [0, -500]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500]),\n  ('control: half cent', (1001, 0, 0, '50'), [501, 1502]), ('control: no surtax', (4200, 100, 0, '0'), [0, 4100]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000])],\n [('regression refundable-order 1', (5225, 20000, 9000, '8'), [0, -9000]),\n  ('regression refundable-order 2', (18855, 20000, 500, '50'), [0, -500]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000]),\n  ('control: credits exceed tax', (1000, 3000, 500, '20'), [0, -500]),\n  ('control: rounding', (333, 0, 0, '1.5'), [5, 338]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500])]]\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"},"fixed":{"sha256":"002c8f821f42b6db947a7b6270b7c29c064abe9b11a8ddc7e3d5931875af77ae","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom fractions import Fraction\nN = 1\nobservations = []\ndef solve(state, nonref, ref, pct):\n    after = max(0, state - nonref)\n    local = int(after * Fraction(pct) / 100 + Fraction(1, 2))\n    return [local, after + local - ref]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncases = [[('regression refundable-order 1', (5000, 1000, 9000, '12.5'), [500, -4500]),\n  ('regression refundable-order 2', (1000, 3000, 500, '20'), [0, -500]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000]),\n  ('control: rounding', (333, 0, 0, '1.5'), [5, 338]), ('control: half cent', (1001, 0, 0, '50'), [501, 1502]),\n  ('control: no surtax', (4200, 100, 0, '0'), [0, 4100])],\n [('regression refundable-order 1', (18157, 72365, 10702, '3.25'), [0, -10702]),\n  ('regression refundable-order 2', (60634, 89812, 9000, '12.5'), [0, -9000]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500]),\n  ('control: half cent', (1001, 0, 0, '50'), [501, 1502]), ('control: no surtax', (4200, 100, 0, '0'), [0, 4100]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000])],\n [('regression refundable-order 1', (7099, 20000, 500, '20'), [0, -500]),\n  ('regression refundable-order 2', (27020, 20000, 9000, '3.25'), [228, -1752]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000]),\n  ('control: credits exceed tax', (1000, 3000, 500, '20'), [0, -500]),\n  ('control: rounding', (333, 0, 0, '1.5'), [5, 338]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500])],\n [('regression refundable-order 1', (4316, 0, 9000, '17.5'), [755, -3929]),\n  ('regression refundable-order 2', (63135, 85065, 500, '20'), [0, -500]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500]),\n  ('control: half cent', (1001, 0, 0, '50'), [501, 1502]), ('control: no surtax', (4200, 100, 0, '0'), [0, 4100]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000])],\n [('regression refundable-order 1', (5225, 20000, 9000, '8'), [0, -9000]),\n  ('regression refundable-order 2', (18855, 20000, 500, '50'), [0, -500]),\n  ('control: typical', (100000, 20000, 5000, '17.5'), [14000, 89000]),\n  ('control: credits exceed tax', (1000, 3000, 500, '20'), [0, -500]),\n  ('control: rounding', (333, 0, 0, '1.5'), [5, 338]),\n  ('control: large refund', (5000, 1000, 9000, '12.5'), [500, -4500])]]\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-local-piggyback-surtax-refundable-order","generated_at":"2026-09-29T14:47:07.199371+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.","repair":"Apply refundable credits in full.","root_cause":"The total after refundable credits is floored at zero.","sha256":"b6637ca895920bce3aa0bcbf886b95cc28ba9c40a857965bc3b72f4630685b68","title":"Refundable credits are limited to the combined tax · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":45.795,"exit_code":1,"observations":[{"actual":[500,500],"check":"regression refundable-order 1","expected":[500,-4500],"passed":false},{"actual":[0,0],"check":"regression refundable-order 2","expected":[0,-500],"passed":false},{"actual":[14000,89000],"check":"control: typical","expected":[14000,89000],"passed":true},{"actual":[5,338],"check":"control: rounding","expected":[5,338],"passed":true},{"actual":[501,1502],"check":"control: half cent","expected":[501,1502],"passed":true},{"actual":[0,4100],"check":"control: no surtax","expected":[0,4100],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression refundable-order 1\", \"actual\": [500, 500], \"expected\": [500, -4500], \"passed\": false}, {\"check\": \"regression refundable-order 2\", \"actual\": [0, 0], \"expected\": [0, -500], \"passed\": false}, {\"check\": \"control: typical\", \"actual\": [14000, 89000], \"expected\": [14000, 89000], \"passed\": true}, {\"check\": \"control: rounding\", \"actual\": [5, 338], \"expected\": [5, 338], \"passed\": true}, {\"check\": \"control: half cent\", \"actual\": [501, 1502], \"expected\": [501, 1502], \"passed\": true}, {\"check\": \"control: no surtax\", \"actual\": [0, 4100], \"expected\": [0, 4100], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":44.897,"exit_code":1,"observations":[{"actual":[500,0],"check":"regression refundable-order 1","expected":[500,-4500],"passed":false},{"actual":[0,0],"check":"regression refundable-order 2","expected":[0,-500],"passed":false},{"actual":[14000,89000],"check":"control: typical","expected":[14000,89000],"passed":true},{"actual":[5,338],"check":"control: rounding","expected":[5,338],"passed":true},{"actual":[501,1502],"check":"control: half cent","expected":[501,1502],"passed":true},{"actual":[0,4100],"check":"control: no surtax","expected":[0,4100],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression refundable-order 1\", \"actual\": [500, 0], \"expected\": [500, -4500], \"passed\": false}, {\"check\": \"regression refundable-order 2\", \"actual\": [0, 0], \"expected\": [0, -500], \"passed\": false}, {\"check\": \"control: typical\", \"actual\": [14000, 89000], \"expected\": [14000, 89000], \"passed\": true}, {\"check\": \"control: rounding\", \"actual\": [5, 338], \"expected\": [5, 338], \"passed\": true}, {\"check\": \"control: half cent\", \"actual\": [501, 1502], \"expected\": [501, 1502], \"passed\": true}, {\"check\": \"control: no surtax\", \"actual\": [0, 4100], \"expected\": [0, 4100], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":42.693,"exit_code":0,"observations":[{"actual":[500,-4500],"check":"regression refundable-order 1","expected":[500,-4500],"passed":true},{"actual":[0,-500],"check":"regression refundable-order 2","expected":[0,-500],"passed":true},{"actual":[14000,89000],"check":"control: typical","expected":[14000,89000],"passed":true},{"actual":[5,338],"check":"control: rounding","expected":[5,338],"passed":true},{"actual":[501,1502],"check":"control: half cent","expected":[501,1502],"passed":true},{"actual":[0,4100],"check":"control: no surtax","expected":[0,4100],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression refundable-order 1\", \"actual\": [500, -4500], \"expected\": [500, -4500], \"passed\": true}, {\"check\": \"regression refundable-order 2\", \"actual\": [0, -500], \"expected\": [0, -500], \"passed\": true}, {\"check\": \"control: typical\", \"actual\": [14000, 89000], \"expected\": [14000, 89000], \"passed\": true}, {\"check\": \"control: rounding\", \"actual\": [5, 338], \"expected\": [5, 338], \"passed\": true}, {\"check\": \"control: half cent\", \"actual\": [501, 1502], \"expected\": [501, 1502], \"passed\": true}, {\"check\": \"control: no surtax\", \"actual\": [0, 4100], \"expected\": [0, 4100], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}