Jet Lag Planner mechanism

Model scope

The honest_label appropriately states that this is an educational rule of thumb and not medical or sleep-disorder advice. Before release, define timezones_crossed precisely, add a rounding policy, provide the missing light-exposure logic and constraints, and require baseline sleep information for a true day-by-day schedule.

• The adjustment formula is underspecified for fractional results: no rounding or schedule-length policy is given when timezones_crossed/1.5 is non-integer.
• The term timezones_crossed is ambiguous: it could mean absolute UTC-offset difference, legal time-zone boundaries crossed, or destination-minus-home offset; daylight-saving changes and the International Date Line are not addressed.
• No formula is provided for the promised light-exposure suggestion.
• The bedtime-shift rule does not define whether eastward means earlier bedtime and westward means later bedtime, nor does it specify how many pre-flight days are available.
• A day-by-day schedule cannot be computed from the listed inputs without a baseline bedtime, wake time, desired sleep window, and schedule start date.

Units and conventions

• timezones_crossed is treated as the absolute difference between home and destination UTC offsets, measured in hours; fractional offsets such as 4.5 hours are allowed.
• direction is eastward when the destination UTC offset is greater than the home offset and westward when it is lower.
• For test arithmetic, eastward adjustment is 1 day per crossed time zone and westward adjustment is 1.5 crossed time zones per day.
• The approximately 1-hour daily bedtime shift is treated as exactly 1 hour for testing; eastward means shifting bedtime 1 hour earlier per day and westward means shifting it 1 hour later per day.
• No clinical light-timing recommendation is inferred because the specification supplies no light-exposure formula.

Inspectable vector

One of 4 source-bound review vectors:

{
  "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."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

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.

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
• BOUNDARY_HAZARD_CATALOG.json