Currency Converter (Offline Snapshot) mechanism

Model scope

The arithmetic method is standard once the quote convention is fixed, but the specification does not provide the actual bundled table or a concrete build-time snapshot date. The verdict is NEEDS_REVIEW until the implementation documents its base currency, exact table values and source/date, supported currencies, validation behavior, and rounding policy.

• The formula description is underspecified: with rates quoted as units of each currency per EUR, the standard cross-rate formula is converted_amount = amount × (rate_to / rate_from).
• The bundled snapshot table itself, its base currency, quote convention, and supported currency codes are not supplied, so the actual implementation cannot be verified from the specification alone.
• Rounding behavior is unspecified, including decimal precision, minor-unit rules, and whether intermediate calculations retain full precision.
• The specification does not define behavior for unsupported currencies, malformed currency codes, negative amounts, or conversion from a currency to itself.

Units and conventions

• Each table rate is quoted as currency units per 1 EUR; EUR has rate 1.000000.
• Amounts are monetary amounts denominated in the input currency, and the result is denominated in the output currency.
• The calculation uses amount × rate_to / rate_from, with no fees, spread, commission, or tax.
• Test outputs show mathematical precision; a production display may round according to the destination currency's minor-unit convention, which must be specified.
• The displayed date is the snapshot date, not the time at which the offline conversion is performed.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "amount": 1,
    "from_currency": "EUR",
    "to_currency": "DEM",
    "snapshot_date": "2025-01-15"
  },
  "expected_outputs": {
    "converted_amount": 1.95583,
    "notice": "Rates as of 2025-01-15; may be stale."
  },
  "reference_data": {
    "rate_rows": [
      {
        "currency": "EUR",
        "units_per_EUR": 1,
        "source_convention": "European Commission/ECB irrevocable euro conversion-rate table"
      },
      {
        "currency": "DEM",
        "units_per_EUR": 1.95583,
        "source_convention": "European Commission/ECB irrevocable euro conversion-rate table"
      }
    ],
    "quote_convention": "units of currency per 1 EUR"
  },
  "working": "EUR rate = 1.00000 units/EUR. DEM rate = 1.95583 units/EUR. Converted amount = 1 EUR × (1.95583 / 1.00000) = 1.95583 DEM. This lands exactly on the official fixed EUR-to-German-mark conversion entry."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The specification does not provide the bundled currency-rate table, its date, supported currency codes, missing-rate behavior, or sign convention. Consequently, ordinary cross-currency conversions cannot be numerically verified from this specification, and unsupported currencies can produce undefined lookup results unless explicitly rejected.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json