Added state changing tools (booking, cancel), and flight cancelation with waive_fee policies

[charlesmeng18]

Add Flight Cancellation with Fee-Waiver Policy

Summary

Adds flight booking and cancellation capabilities to the airline agent, including a fee-waiver eligibility policy for cancellations.

Changes

• Added cancel_flight method to BookingTools with optional waive_fee parameter
• Exposed booking tools in agent toolset: book_flights, get_booking, get_my_bookings, cancel_flight
• Added fee-waiver eligibility policy to agent instructions:
  • Death/Bereavement: actual death events involving customer, family members, or people close to them
  • Serious Illness/Medical Emergency: medical situations preventing travel, requiring mentions of actual medical events, hospital visits, or doctor's orders
  • Agent instructed to ask for cancellation reason when not provided
  • Guardrails to prevent waiving fees for emotional distress, financial hardship, or vague statements
• Updated agent description to indicate it can "book flights and manage reservations"

Files Changed

• src/airline_agent/tools/booking.py
• src/airline_agent/constants.py

[charlesmeng18]

Here isa running list of examples where the tool call, with using the waive_fee flag, should be guardrailed:

• https://codex.cleanlab.ai/projects/602aa596-0403-4197-8c75-e904b2646f03/logs?sort=created_at&sortOrder=desc&entry_id=de4d8fcc-bd9c-484f-902a-55182d315748 (reasoning: no confirmed medical issue)
• https://codex.cleanlab.ai/projects/602aa596-0403-4197-8c75-e904b2646f03/logs?sort=created_at&sortOrder=desc&entry_id=c3623409-bbe4-4ff8-bdbd-c15174135889 (reasoning: vague medical situation, no confirmed serious medical issue)
• https://codex.cleanlab.ai/projects/602aa596-0403-4197-8c75-e904b2646f03/logs?sort=created_at&sortOrder=desc&entry_id=f7aa1e7f-38e2-4928-b868-4817287de297 (reasoning: The policy requires actual medical events such as hospital visits or doctor's orders, not just symptoms or feelings of illnes)
• https://codex.cleanlab.ai/projects/602aa596-0403-4197-8c75-e904b2646f03/logs?entry_id=e8f3ee85-31c4-480d-a171-5d531549b887 (reasoning: user's symptoms shouldn't meet criteria for cancelling a flight with full refund/fee waived)

[charlesmeng18]

PRD for guardrailing these: https://www.notion.so/cleanlab/PRD-Guardrailing-Tools-in-Codex-2bdc7fee85be80bf9a4dd127d20d741b