Source: https://guthlabs.ai/docs/instruments/meal-prep-portion-calculator/implementation/

instrument implementation / implementation-contract

# Meal Prep Portion Calculator implementation

A source-bound implementation contract for Meal Prep Portion Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## 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**: t5-145

**Effect**: Computation or source lookup only

## Input and validation requirements

The calculator reaches undefined results when num_portions is zero and should reject that input. A separate convention hazard exists when the total yield has no explicit unit, although the arithmetic remains numerically valid.

## 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": {
    "total_qty": 2400,
    "total_qty_unit": "g",
    "num_portions": 6,
    "total_macros": {
      "calories": 3600,
      "protein_g": 180,
      "carbohydrates_g": 300,
      "fat_g": 120
    }
  },
  "expected_outputs": {
    "portion_qty": 400,
    "portion_qty_unit": "g",
    "per_portion_macros": {
      "calories": 600,
      "protein_g": 30,
      "carbohydrates_g": 50,
      "fat_g": 20
    }
  },
  "working": "portion_qty = 2400 g / 6 = 400 g. Calories = 3600 kcal / 6 = 600 kcal. Protein = 180 g / 6 = 30 g. Carbohydrates = 300 g / 6 = 50 g. Fat = 120 g / 6 = 20 g."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/meal-prep-portion-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/meal-prep-portion-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/meal-prep-portion-calculator/qualification/>)

## 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`