Jet Lag Planner 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

t4-175

Effect

Computation or source lookup only

Input and validation requirements

The arithmetic itself has no division-by-zero trap, but the specification does not define a precise light-exposure algorithm or an unambiguous sign convention for bedtime shifts. Consequently, concrete light timing and consistently signed schedules cannot be generated without additional conventions.

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": {
    "home_zone": "America/New_York",
    "destination_zone": "Asia/Tokyo",
    "travel_date": "2026-04-10",
    "home_utc_offset_hours": -5,
    "destination_utc_offset_hours": 9,
    "direction": "eastward",
    "timezones_crossed": 14
  },
  "expected_outputs": {
    "days_to_adjust": 14,
    "bedtime_shift_hours_per_day": -1,
    "bedtime_shift_direction": "earlier",
    "light_exposure": "undetermined_by_spec"
  },
  "working": "UTC-offset difference = 9 - (-5) = 14 hours. Eastward rate = 1 timezone/day. Days to adjust = 14 / 1 = 14 days. Bedtime shift = 1 hour/day earlier, represented as -1 hour/day."
}

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-tranche4/tranche4-results.json