{
      "tool_id": "art-338-compute-federal-withholding",
      "tool_version": "1.0.0",
      "display_name": "Federal Withholding Calculator (Percentage Method)",
      "mcp_name": "compute_federal_withholding",
      "mandate_type": "compliance_mandate",
      "wave": 60,
      "gpu": false,
      "url": "https://ainumbers.co/chaingraph/art-338-compute-federal-withholding.html",
      "description": "Federal income tax withholding via the IRS Publication 15-T (2025) percentage method, Worksheet 1A, for a 2020-or-later Form W-4. Supports single/MFS, married filing jointly, and head of household, plus Step 3 dependents credit, Step 4(a) other income, Step 4(b) deductions, and Step 4(c) extra withholding. STANDARD Withholding Rate Schedules only; the Form W-4 Step 2 multiple-jobs checkbox table is out of scope for v1. Federal only, not tax advice, state withholding out of scope. Feeds art-339-compute-gross-to-net as its federal_withholding_per_period input. Not compute_gross_to_net itself, which adds FICA and produces net pay.",
      "input_schema_ref": "chaingraph/art-338-compute-federal-withholding.html#manifest",
      "consumes": [],
      "feeds": [
        "art-339-compute-gross-to-net"
      ],
      "status": "live",
      "conformance_fixtures": true,
      "compute_capability": "server",
      "compute_images": [{"system":"sha256-source","image_id":"sha256:510689cdacc57d0934a872451735f41f2e58e4b71158ca7acf61f3738a74936b","valid_from":"2026-07-10"},{"system":"risc0","image_id":"sha256:a1a0bc89b5b1febaeda3519f6dbade0fa5ac16beeb143c4e1b01689573567bc6","valid_from":"2026-07-17"}],
      "export_capability": [
        "json"
      ],
      "compute_proof_ready": "ready",
      "compute_proof": {
        "type": "ZkVmReceipt",
        "system": "risc0",
        "receiptFormat": "groth16-bn254",
        "imageId": "sha256:a1a0bc89b5b1febaeda3519f6dbade0fa5ac16beeb143c4e1b01689573567bc6",
        "seal": "CgThEFm1coJPCB2VulvL8LCrPH9s2JG03IEQVyNzCFMTEccP13R5TuhiVqYbIgkl3qMiiB7l1dGt2K6rXlwNMwKPKXab91GZjWQ54tHdL24UwP+C/BR47AYG5OkN61PUJxpdK6jeuwq4arGbjOARe+wjK/J1f7pXLHQ8gTLZLr0UwuqSG36J02gQ3F31dqllZGao1C1vHElJUNlHaCB2BgOnHrJdtS855XR4aiL+CDtQts/Ntd9kXdPdRBQ0TKr3AkZTXbujTmhWNXp9UhLoDd+qtgzXVLgYLd9Gpjl1C30FNV8E12e+4gBePNqdYpvVoYosQWGdX2058dnBXVGt5g==",
        "journal": {
          "chaingraph_version": "0.4.0",
          "kernel_digest": "sha256:510689cdacc57d0934a872451735f41f2e58e4b71158ca7acf61f3738a74936b",
          "output": {
            "adjusted_annual_wage_amount": 43400,
            "bracket_at_least": 18325,
            "bracket_rate": 0.12,
            "constants_version": "2025",
            "federal_withholding_per_period": 161.6,
            "filing_status": "single_or_mfs",
            "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.",
            "pay_frequency": "biweekly",
            "periods_per_year": 26,
            "regulatory_basis": "IRS Publication 15-T (2025), Section 4, Percentage Method Tables for Automated Payroll Systems; Worksheet 1A.",
            "step3_credit_this_period": 0,
            "step4c_extra_withholding_per_period": 0,
            "tentative_annual_withholding": 4201.5,
            "tentative_withholding_this_period": 161.6
          }
        }
      }
    }