{
  "tool_id": "art-338-compute-federal-withholding",
  "note": "golden_hash filled by golden-parity.test.mjs --update. Vector 1: biweekly single filer, no Step 3/4 adjustments, 12% bracket. Vector 2: weekly single filer exercising every Worksheet 1A adjustment line (Step 3 credit, Step 4(a) other income, Step 4(b) deductions, Step 4(c) extra withholding), 24% bracket. Vector 3: zero-wage edge (finite gate).",
  "vectors": [
    {
      "name": "biweekly_single_standard",
      "description": "$2,000 biweekly gross, single or MFS, no adjustments. Adjusted Annual Wage Amount = $2,000*26 - $8,600 = $43,400, falling in the 12% bracket ($18,325-$54,875, base $1,192.50). Tentative annual withholding = $1,192.50 + ($43,400-$18,325)*0.12 = $4,201.50; per-period = $4,201.50/26 = $161.60.",
      "policy_parameters": {
        "gross_wages_per_period": 2000,
        "pay_frequency": "biweekly",
        "filing_status": "single_or_mfs"
      },
      "output_payload": {
        "federal_withholding_per_period": 161.6,
        "pay_frequency": "biweekly",
        "periods_per_year": 26,
        "filing_status": "single_or_mfs",
        "adjusted_annual_wage_amount": 43400,
        "bracket_at_least": 18325,
        "bracket_rate": 0.12,
        "tentative_annual_withholding": 4201.5,
        "tentative_withholding_this_period": 161.6,
        "step3_credit_this_period": 0,
        "step4c_extra_withholding_per_period": 0,
        "constants_version": "2025",
        "regulatory_basis": "IRS Publication 15-T (2025), Section 4, Percentage Method Tables for Automated Payroll Systems; Worksheet 1A.",
        "note": "STANDARD Withholding Rate Schedules only (Form W-4 Step 2 multiple-jobs checkbox not supported in v1). Federal withholding only; not tax advice; state and local withholding out of scope."
      },
      "compliance_flags": [
        "MULTIPLE_JOBS_CHECKBOX_NOT_SUPPORTED_V1",
        "FEDERAL_ONLY_NOT_TAX_ADVICE"
      ],
      "golden_hash": "09f2bb0adb4a4bafcc4dd009d101604703beee2061bdaa6734d7089c972b8368"
    },
    {
      "name": "weekly_single_full_worksheet",
      "description": "$2,500 weekly gross, single or MFS, Step 3 dependents credit $2,000/yr, Step 4(a) other income $5,000/yr, Step 4(b) deductions $3,000/yr, Step 4(c) extra withholding $25/period. Adjusted Annual Wage Amount = ($2,500*52 + $5,000) - ($3,000 + $8,600) = $135,000 - $11,600 = $123,400, in the 24% bracket ($109,750-$203,700, base $17,651.00). Tentative annual = $17,651 + ($123,400-$109,750)*0.24 = $20,927.00; per-period = $20,927/52 = $402.4423 -> $402.44. Step 3 credit per period = $2,000/52 = $38.4615 -> $38.46. Final = $402.44 - $38.46 + $25 = $388.98.",
      "policy_parameters": {
        "gross_wages_per_period": 2500,
        "pay_frequency": "weekly",
        "filing_status": "single_or_mfs",
        "step3_dependents_credit_annual": 2000,
        "step4a_other_income_annual": 5000,
        "step4b_deductions_annual": 3000,
        "step4c_extra_withholding_per_period": 25
      },
      "output_payload": {
        "federal_withholding_per_period": 388.98,
        "pay_frequency": "weekly",
        "periods_per_year": 52,
        "filing_status": "single_or_mfs",
        "adjusted_annual_wage_amount": 123400,
        "bracket_at_least": 109750,
        "bracket_rate": 0.24,
        "tentative_annual_withholding": 20927,
        "tentative_withholding_this_period": 402.44,
        "step3_credit_this_period": 38.46,
        "step4c_extra_withholding_per_period": 25,
        "constants_version": "2025",
        "regulatory_basis": "IRS Publication 15-T (2025), Section 4, Percentage Method Tables for Automated Payroll Systems; Worksheet 1A.",
        "note": "STANDARD Withholding Rate Schedules only (Form W-4 Step 2 multiple-jobs checkbox not supported in v1). Federal withholding only; not tax advice; state and local withholding out of scope."
      },
      "compliance_flags": [
        "MULTIPLE_JOBS_CHECKBOX_NOT_SUPPORTED_V1",
        "FEDERAL_ONLY_NOT_TAX_ADVICE"
      ],
      "golden_hash": "073f0ba94a2900b59f994866c56ad6e7b0bda089a8a11de59626add229b75952"
    },
    {
      "name": "zero_wages_edge",
      "description": "Zero gross wages this period. Finite gate: all downstream figures must resolve to 0, never NaN/Infinity, and WITHHOLDING_ZERO_WAGES flags.",
      "policy_parameters": {
        "gross_wages_per_period": 0,
        "pay_frequency": "biweekly",
        "filing_status": "single_or_mfs"
      },
      "output_payload": {
        "federal_withholding_per_period": 0,
        "pay_frequency": "biweekly",
        "periods_per_year": 26,
        "filing_status": "single_or_mfs",
        "adjusted_annual_wage_amount": 0,
        "bracket_at_least": 0,
        "bracket_rate": 0,
        "tentative_annual_withholding": 0,
        "tentative_withholding_this_period": 0,
        "step3_credit_this_period": 0,
        "step4c_extra_withholding_per_period": 0,
        "constants_version": "2025",
        "regulatory_basis": "IRS Publication 15-T (2025), Section 4, Percentage Method Tables for Automated Payroll Systems; Worksheet 1A.",
        "note": "STANDARD Withholding Rate Schedules only (Form W-4 Step 2 multiple-jobs checkbox not supported in v1). Federal withholding only; not tax advice; state and local withholding out of scope."
      },
      "compliance_flags": [
        "MULTIPLE_JOBS_CHECKBOX_NOT_SUPPORTED_V1",
        "FEDERAL_ONLY_NOT_TAX_ADVICE",
        "WITHHOLDING_ZERO_WAGES"
      ],
      "golden_hash": "dd5d8ffeafc53809351f07e29bf09c292f57d396a9e84a9934da62d2eca263af"
    }
  ]
}