Grocery Recipe Cost Estimator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t5-092

Effect

Computation or source lookup only

Input and validation requirements

The formula has an unhandled zero-denominator case when purchase_qty is zero, which can yield Infinity in plain JavaScript instead of a rejected input. Mixed quantity units can also produce a 1,000-fold cost error if no unit convention or conversion is enforced.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "ingredients": [
      {
        "name": "flour",
        "purchase_qty": 2,
        "purchase_unit": "kg",
        "purchase_price": 4.8,
        "qty_used": 0.5,
        "used_unit": "kg"
      },
      {
        "name": "sugar",
        "purchase_qty": 1,
        "purchase_unit": "kg",
        "purchase_price": 2.5,
        "qty_used": 0.2,
        "used_unit": "kg"
      },
      {
        "name": "eggs",
        "purchase_qty": 12,
        "purchase_unit": "count",
        "purchase_price": 3.6,
        "qty_used": 3,
        "used_unit": "count"
      }
    ],
    "servings": 8
  },
  "expected_outputs": {
    "total_cost": 2.6,
    "per_serving": 0.325
  },
  "working": "Flour: (0.5 kg / 2 kg) × $4.80 = 0.25 × $4.80 = $1.20. Sugar: (0.2 kg / 1 kg) × $2.50 = 0.20 × $2.50 = $0.50. Eggs: (3 / 12) × $3.60 = 0.25 × $3.60 = $0.90. Total cost = $1.20 + $0.50 + $0.90 = $2.60. Per serving = $2.60 / 8 = $0.325."
}

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-tranche5/tranche5-results.json