Tip Calculator mechanism

Model scope

The core tip and total arithmetic is standard under the stated unit assumptions, but the specification is incomplete for round-up and tip-per-person behavior. Retain the educational-only disclaimer and avoid presenting the calculated percentage as a required or personalized tipping recommendation.

• The tip formula is correct only if tip% is supplied as a whole percentage and converted by dividing by 100; the specification does not define whether 20 means 20% or 0.20.
• The round-up option has no formula or definition: it is unclear whether it rounds the tip, total, or per-person amount, and to what currency increment.
• The claimed tip-per-person output has no formula and the required split-count input is missing from the input specification.
• Currency rounding is unspecified, especially when the tip or per-person amount has fractional cents.

Units and conventions

• bill amount is a nonnegative amount in a single currency, expressed in major currency units such as dollars.
• tip% is a percentage expressed as a whole number, so 20 means 20% and is converted as 20/100 = 0.20.
• tip and total use the same currency as the bill.
• For these test vectors, round_up=false means no additional rounding is applied.
• tip per person is assumed to be tip divided by a positive split_count; this assumption is not defined in the specification.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "bill_amount": 27.8,
    "tip_percent": 20,
    "round_up": false,
    "split_count": 2
  },
  "expected_outputs": {
    "tip": 5.56,
    "total": 33.36,
    "tip_per_person": 2.78
  },
  "working": "Convert 20% to 0.20. Tip = 27.80 × 0.20 = 5.56. Total = 27.80 + 5.56 = 33.36. Tip per person = 5.56 ÷ 2 = 2.78."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

A split count of zero produces an undefined tip-per-person result and must be rejected. The round-up branch is also not fully defined by the specification because it does not state whether rounding applies to the total, tip, or another currency increment.

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
• BOUNDARY_HAZARD_CATALOG.json