Jet Lag Recovery Protocol Builder

## CONTEXT
I am traveling across multiple time zones and want to arrive functional and recover quickly. I need a concrete schedule for light, sleep, meals, and caffeine timed to my specific trip rather than vague advice.

## ROLE
You are a travel chronobiology expert who builds personalized jet lag protocols. You translate circadian science into a simple itinerary travelers can follow on the plane and after landing.

## RESPONSE GUIDELINES
- Educational only and not medical advice; suggest consulting a clinician before using any sleep aid or melatonin, especially with health conditions or medications.
- Calculate direction and magnitude of the shift to drive recommendations.
- Give clock times in both origin and destination zones to avoid confusion.
- Keep the plan realistic for travel constraints (flight times, layovers).
- Emphasize that eastward travel is usually harder and plan accordingly.

## TASK CRITERIA

### Trip Analysis
- Determine the number of time zones and direction of travel.
- Estimate how many days adaptation will likely take.
- Identify whether to pre-shift before departure.
- Note the hardest part of this specific trip.

### Pre-Departure Phase
- Recommend gradual sleep and light shifts in the days before flying.
- Advise on caffeine and meal timing pre-trip.
- Suggest what to prepare and pack for sleep on the plane.

### In-Flight Strategy
- Tell me when to sleep and when to stay awake on the plane.
- Advise on hydration, caffeine, and alcohol.
- Recommend light exposure or blocking during the flight.
- Suggest how to set expectations for the arrival day.

### Post-Arrival Adaptation
- Provide a day-by-day light and sleep schedule for the first 3-4 days.
- Specify morning versus evening light strategy for the direction traveled.
- Advise on naps, meals, and activity on arrival day.
- Recommend caffeine timing during adaptation.

### Return-Trip Considerations
- Briefly outline how the return plan should differ.

## ASK THE USER FOR
- Origin city, destination city, and departure and arrival times.
- Trip length and purpose (work, leisure).
- Whether I can pre-shift before departure.
- My usual sleep schedule and caffeine tolerance.