Auto-Loan Disclosure Verifier

Note (dated 2026-08-04): a chain composes independent computations performed in an analytical order. No step's output is carried into the next step by the execution model; each step computes from its own declared inputs. This is true of every chain on this site, including chains whose per-step copy below reads as a data handoff.

Two-step chain. Step 1 rebuilds the auto-loan amortization schedule from amount financed, rate, and term. Step 2 checks the disclosed Amount Financed, Finance Charge, and Total of Payments against the recomputed totals under 12 CFR 1026.18. APR is not checked in v1.

OpenChainGraph · 2 Steps compliance mandate · TILA 1026.18 Hash-Anchored §4 chain_depth:2 Client-Side · Zero PII

Chain Stages · 2 Steps · Linear

1 ROOT node

Amortization Schedule Builder art-332-build-amortization-schedule

Rebuilds the level-payment amortization schedule from the contract terms; totals and schedule digest are cited at step 2.

MCP Call · build_amortization_schedule

{
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "name": "build_amortization_schedule",
    "arguments": {
      "policy_parameters": {
        "schedule_type": "level_payment",
        "loan_amount": 28000,
        "note_rate_pct": 9.9,
        "num_payments": 72,
        "periods_per_year": 12
      }
    }
  },
  "id": 1
}

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2 TERMINAL node

Retail Installment Contract TILA Disclosure Checker art-404-check-retail-installment-disclosures

Checks the disclosed Amount Financed, Finance Charge, and Total of Payments against the step-1 totals and digest. Dealer participation is self-declared, not detected. Final stage.

MCP Call · check_retail_installment_disclosures

{
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "name": "check_retail_installment_disclosures",
    "arguments": {
      "policy_parameters": {
        "inputs": {
          "cash_price": 29500,
          "downpayment": 1500,
          "amortization_schedule": {
            "totals": {"total_interest": 9246.59, "total_principal": 28000, "num_payments": 72, "ending_balance": 0},
            "schedule_digest": "sha256:e415c2... (from step 1)",
            "source_tool_id": "art-332-build-amortization-schedule"
          },
          "disclosed_amount_financed": 28000,
          "disclosed_finance_charge": 9246.59,
          "disclosed_total_of_payments": 37246.59,
          "tolerance_cents": 1000
        }
      }
    }
  },
  "id": 2
}

Chain Notes

Tolerance rule (12 CFR 1026.18(d)(2)). The disclosed finance charge is treated as accurate when, "in a transaction involving an amount financed of $1,000 or less, it is not more than $5 above or below the amount required to be disclosed; or, in a transaction involving an amount financed of more than $1,000, it is not more than $10 above or below the amount required to be disclosed." In practice: $5 tolerance at $1,000 or less financed, $10 tolerance above $1,000 financed.

Dealer participation. Any dealer markup figure is self-declared, not detected. The chain records the borrower's assertion and flags an undisclosed markup; it computes no discrimination finding.

Scope. Amount Financed, Finance Charge, and Total of Payments only. APR is not checked in v1. Federal TILA math only.

Question: What is the finance charge on a $28,000 auto loan at 9.9% for 72 months, and how does it move if the amount financed is $30,000? Run the AINumbers MCP tool `run_chain` with {"chain":"auto-loan-disclosure-verifier"} and read `art-332-build-amortization-schedule.totals.total_interest`. Re-run with `inputs` for `art-332-build-amortization-schedule`, reusing the values that result echoed, with `loan_amount` set to 30000. Compare the same field. Verify: call `verify_execution_hash` (https://mcp.ainumbers.co/mcp) with `claimed_hash` set to `composite_execution_hash` and the full `composite_artifact`. Ledger, for a human re-check: https://ledger.ainumbers.co/ PII rule: send synthetic or anonymised inputs only. The MCP server runs these kernels and logs no payloads. Chain page: https://ainumbers.co/chaingraph/chains/auto-loan-disclosure-verifier.html

Auto-Loan Disclosure Verifier

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