You MUST use a todo list to complete these steps in order. Never move on to one step if you haven't completed the previous step. If you have multiple read steps in a row, read them all at once (in parallel).

Add all steps to your todo list now and begin executing.

## Steps

1. Identify which trip to update. Check `./documents/trips/*.yaml` for existing trips.
If user mentioned a specific trip by name or destination, match it. If multiple trips could match (e.g., two Paris trips), ask which one. If no trip specified and only one exists, use that. If no trips exist, redirect to creating one first.

2. Read the trip file from `./documents/trips/*.yaml` to get current state.

3. [Read Trip Data Format]: Read the documentation in: `./skills/sauna/[skill_id]/references/travel.trip.format.md`

4. Determine what kind of update the user wants. They might be:
**Planning ahead** (adding future items): - 'Add dinner at 7pm tomorrow' - 'Book the Eiffel Tower tour for Saturday' - 'We're staying at Hotel X'
**Logging activity** (recording what happened): - 'Just finished the museum' - 'Had lunch at Cafe Flore, it was great' - 'Spent €50 on souvenirs'
**Modifying plans**: - 'Cancel the restaurant reservation' - 'Move the tour to afternoon' - 'We're skipping the day trip'
**Updating status**: - 'We're starting the trip!' → status: in-progress - 'Trip's over' → status: completed

5. Apply the update to the trip file:
**For new itinerary entries**: Add to the appropriate date with time, activity, location, type. Default status is 'planned' for future items.
**For logging completions**: Find the matching entry (or create if it was spontaneous) and set status to 'completed'. Add notes about how it went, actual duration, etc.
**For bookings**: Add to the appropriate section (flights, hotels, reservations, other) with all confirmation details provided.
**For expenses**: Add to budget.expenses with date, item, amount, category.
**For cancellations**: Either remove the entry or set status to 'skipped' (prefer skipped if they might reschedule).
**For modifications**: Update the relevant fields (time, location, notes).
Write the updated file back to `./documents/trips/*.yaml`

6. Confirm the update. Be brief but specific: - What was added/changed - Any follow-up needed (e.g., 'Want to add the confirmation number?')
If they logged an expense, mention running total if budget was set.