Mortgage APR Accuracy and Tolerance Cure

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.

Linear three-step TRID remediation chain. Computes the actual APR from Reg Z Appendix J parameters, verifies APR accuracy against the disclosed figure, and produces a complete TRID fee tolerance cure package. Use this chain when you need to both diagnose an APR disclosure error and quantify the cure amount for loan remediation.

OpenChainGraph · 3 Steps compliance mandate · TRID Cure Hash-Anchored §4 chain_depth:3 Client-Side · Zero PII

Chain Stages · 3 Steps · Linear

1 ROOT node

Reg Z Appendix J APR Solver art-215-reg-z-appendix-j-apr

Actual APR feeds TRID accuracy check at step 2

MCP Call · compute_reg_z_appendix_j_apr

{
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "name": "compute_reg_z_appendix_j_apr",
    "arguments": {
      "loan_amount": 400000,
      "payment_amount": 2528.27,
      "num_payments": 360,
      "periods_per_year": 12
    }
  },
  "id": 1
}

↓

2 MIDDLE node

TRID APR Accuracy Verifier art-217-trid-apr-accuracy

APR accuracy verdict and flags inform cure requirement

MCP Call · verify_trid_apr_accuracy

{
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "name": "verify_trid_apr_accuracy",
    "arguments": {
      "disclosed_apr_pct": 6.875,
      "actual_apr_pct": 6.875
    }
  },
  "id": 2
}

↓

3 TERMINAL node

TRID Fee Tolerance and Cure art-216-trid-tolerance-cure

Cure amount and fee analysis — final stage

MCP Call · compute_trid_tolerance_cure

{
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "name": "compute_trid_tolerance_cure",
    "arguments": {
      "fees": [
        {"name": "Origination fee", "bucket": "zero_tolerance", "le_amount": 1500, "cd_amount": 1500},
        {"name": "Appraisal fee", "bucket": "ten_pct_cumulative", "le_amount": 600, "cd_amount": 640},
        {"name": "Title service", "bucket": "ten_pct_cumulative", "le_amount": 1200, "cd_amount": 1250}
      ]
    }
  },
  "id": 3
}

Question: The disclosed APR sits a few basis points above our recomputation. Does it stay inside the Reg Z tolerance? Run the AINumbers MCP tool `run_chain` with {"chain":"mortgage-apr-accuracy-and-tolerance-cure"} and read `art-217-trid-apr-accuracy.verdict`. Re-run with `inputs` for `art-217-trid-apr-accuracy`, reusing the values that result echoed, with `disclosed_apr_pct` set to 7.5. 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/mortgage-apr-accuracy-and-tolerance-cure.html

Mortgage APR Accuracy and Tolerance Cure

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