Tabular Contract Audit

{
  "assumptions": [
    "Values are compared as the text supplied. No locale, thousands separator or ambiguous date order is inferred, so normalise before auditing if your source uses them.",
    "An empty field is treated as absent, because a literal empty string cannot be distinguished from a missing value in delimited text."
  ],
  "column_count": 5,
  "column_profiles": [
    {
      "declared_type": "integer",
      "distinct_count": 2,
      "inferred_type": "integer",
      "inferred_type_counts": {
        "integer": 3
      },
      "max_length": 4,
      "max_numeric": 1002,
      "min_length": 4,
      "min_numeric": 1001,
      "name": "order_id",
      "null_count": 0,
      "null_rate": 0,
      "present": true
    },
    {
      "declared_type": "string",
      "distinct_count": 3,
      "inferred_type": "string",
      "inferred_type_counts": {
        "string": 3
      },
      "max_length": 3,
      "max_numeric": null,
      "min_length": 3,
      "min_numeric": null,
      "name": "currency",
      "null_count": 0,
      "null_rate": 0,
      "present": true
    },
    {
      "declared_type": "number",
      "distinct_count": 3,
      "inferred_type": "number",
      "inferred_type_counts": {
        "integer": 1,
        "number": 2
      },
      "max_length": 5,
      "max_numeric": 42.5,
      "min_length": 2,
      "min_numeric": -3,
      "name": "amount",
      "null_count": 0,
      "null_rate": 0,
      "present": true
    }
  ],
  "complete": true,
  "encoding": {
    "byte_order_mark": false,
    "crlf_line_endings": false,
    "mixed_line_endings": false,
    "replacement_characters": 0
  },
  "header": {
    "declared": [
      "order_id",
      "currency",
      "amount"
    ],
    "duplicated": [],
    "missing": [],
    "observed": [
      "order_id",
      "currency",
      "amount"
    ],
    "order_changed": false,
    "unexpected": []
  },
  "limitations": [
    "Structural and value-level conformance against the supplied contract only. Business meaning, referential integrity against other datasets, and whether the contract itself is correct are not assessed.",
    "Row, column, cell and violation bounds are applied before and during the audit. Anything left unexamined is named in not_examined, and passed is false whenever complete is false.",
    "Patterns use a documented non-backtracking subset with no groups or alternation, so a native regular expression relying on those will be refused rather than approximated."
  ],
  "limits": {
    "maxCellLength": 4096,
    "maxColumns": 64,
    "maxCsvBytes": 262144,
    "maxEnumValues": 100,
    "maxRows": 5000,
    "maxSafeInteger": 9007199254740991,
    "maxViolations": 500,
    "patternAtoms": 64,
    "patternValueLength": 256
  },
  "not_examined": [],
  "observed_at": "2026-10-02T00:00:00.000Z",
  "passed": false,
  "request_id": "example-request",
  "row_count": 3,
  "service_id": "tabular_contract_audit",
  "service_version": "1.0.0",
  "supplied_row_count": 3,
  "violation_count": 6,
  "violations": [
    {
      "code": "BELOW_MINIMUM",
      "column": "amount",
      "detail": "Row 3: amount is -3, below the declared minimum 0.",
      "row": 3,
      "value": "-3"
    },
    {
      "code": "TYPE_MISMATCH",
      "column": "placed_at",
      "detail": "Row 3: placed_at is declared date but \"2026-09-31\" reads as string.",
      "row": 3,
      "value": "2026-09-31"
    },
    {
      "code": "DUPLICATE_VALUE",
      "column": "order_id",
      "detail": "Row 4: order_id repeats \"1001\", first seen at row 2.",
      "row": 4,
      "value": "1001"
    }
  ],
  "violations_by_code": {
    "BELOW_MINIMUM": 1,
    "DUPLICATE_PRIMARY_KEY": 1,
    "DUPLICATE_VALUE": 1,
    "NOT_IN_ENUM": 1,
    "NULL_RATE_EXCEEDED": 1,
    "TYPE_MISMATCH": 1
  },
  "warnings": []
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://api.zfinia.com/x402/v1/tabular-contract-audit' \
  -H 'content-type: application/json' \
  --data-raw '{"contract":{"columns":[{"name":"order_id","required":true,"type":"integer","unique":true},{"enum":["USD","EUR"],"name":"currency","required":true,"type":"string"},{"min":0,"name":"amount","required":true,"type":"number"},{"name":"placed_at","required":true,"type":"date"},{"max_null_rate":0.1,"name":"email","type":"string"}],"primary_key":["order_id"]},"csv":"order_id,currency,amount,placed_at,email\n1001,USD,42.50,2026-09-30,[email protected]\n1002,EUR,-3,2026-09-31,\n1001,GBP,19.99,2026-10-01,[email protected]\n"}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://api.zfinia.com/x402/v1/tabular-contract-audit' \
  -H 'content-type: application/json' \
  --data-raw '{"contract":{"columns":[{"name":"order_id","required":true,"type":"integer","unique":true},{"enum":["USD","EUR"],"name":"currency","required":true,"type":"string"},{"min":0,"name":"amount","required":true,"type":"number"},{"name":"placed_at","required":true,"type":"date"},{"max_null_rate":0.1,"name":"email","type":"string"}],"primary_key":["order_id"]},"csv":"order_id,currency,amount,placed_at,email\n1001,USD,42.50,2026-09-30,[email protected]\n1002,EUR,-3,2026-09-31,\n1001,GBP,19.99,2026-10-01,[email protected]\n"}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.12 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.12" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.12 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.zfinia.com%2Fx402%2Fv1%2Ftabular-contract-audit&method=POST
const res = await pay("https://api.zfinia.com/x402/v1/tabular-contract-audit", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "contract": {
      "columns": [
        {
          "name": "order_id",
          "required": true,
          "type": "integer",
          "unique": true
        },
        {
          "enum": [
            "USD",
            "EUR"
          ],
          "name": "currency",
          "required": true,
          "type": "string"
        },
        {
          "min": 0,
          "name": "amount",
          "required": true,
          "type": "number"
        },
        {
          "name": "placed_at",
          "required": true,
          "type": "date"
        },
        {
          "max_null_rate": 0.1,
          "name": "email",
          "type": "string"
        }
      ],
      "primary_key": [
        "order_id"
      ]
    },
    "csv": "order_id,currency,amount,placed_at,email\n1001,USD,42.50,2026-09-30,[email protected]\n1002,EUR,-3,2026-09-31,\n1001,GBP,19.99,2026-10-01,[email protected]\n"
  }),
});
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.12 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.12"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://api.zfinia.com/x402/v1/tabular-contract-audit",
        json={
            "contract": {
                "columns": [
                    {
                        "name": "order_id",
                        "required": True,
                        "type": "integer",
                        "unique": True,
                    },
                    {
                        "enum": [
                            "USD",
                            "EUR",
                        ],
                        "name": "currency",
                        "required": True,
                        "type": "string",
                    },
                    {
                        "min": 0,
                        "name": "amount",
                        "required": True,
                        "type": "number",
                    },
                    {
                        "name": "placed_at",
                        "required": True,
                        "type": "date",
                    },
                    {
                        "max_null_rate": 0.1,
                        "name": "email",
                        "type": "string",
                    },
                ],
                "primary_key": [
                    "order_id",
                ],
            },
            "csv": "order_id,currency,amount,placed_at,email\n1001,USD,42.50,2026-09-30,[email protected]\n1002,EUR,-3,2026-09-31,\n1001,GBP,19.99,2026-10-01,[email protected]\n",
        },
    )
    print(res.status_code, res.text)