TripPilot

A WhatsApp travel agent that turns a messy trip request ("need goa trip for 4 ppl next month, budget 60k, hotel near beach") into live-priced flight + hotel quotes, a final itinerary, and (bonus) a test-mode flight booking.

How it works

WhatsApp → Twilio → ngrok → POST /whatsapp (main.py)
                                   │
                              agent.run()  ←── cli.py uses the same function
                                   │
                    Gemini (llm.py) ⇄ tools (function calling, max 6 rounds)
                                   │
       search_flights / search_hotels (SerpAPI) → build_quote / build_itinerary (planner.py)
                                   │
                              book_flight (demo booking; Duffel test mode optional)

• No agent framework: the loop in agent.py is ~40 lines of plain Python.
• The LLM never does maths: search results are stored on the user's session and tools/planner.py computes every rupee.
• Results are trimmed before Gemini sees them, which saves tokens.
• SerpAPI responses are cached in cache/ while USE_CACHE=true.
• Replies go back as TwiML inside the webhook response (trial accounts can't send free-form WhatsApp messages via the REST API). Flight and hotel searches run in parallel to stay under Twilio's ~15s webhook limit; if they're slower, the bot says "still fetching" and delivers the result on the next message.
• After a booking, a PDF confirmation (tools/pdf.py) is attached to the WhatsApp reply.

Setup

py -3.12 -m venv .venv
.venv\Scripts\activate            # macOS/Linux: source .venv/bin/activate
pip install -r requirements.txt
copy .env.example .env            # then fill in the keys

Key	Where to get it
GEMINI_API_KEY, GEMINI_MODEL	aistudio.google.com (use the newest stable Flash model name)
SERPAPI_KEY	serpapi.com dashboard
TWILIO_*	Twilio console → Messaging → Try WhatsApp
DUFFEL_API_KEY	Optional. Only with BOOKING_PROVIDER=duffel; test mode key (duffel_test_...)

Run

pytest                                   # offline tests, no keys needed
python cli.py                            # chat in the terminal
uvicorn main:app --reload --port 8000    # WhatsApp server
ngrok http 8000                          # set https://<ngrok>/whatsapp as the sandbox webhook

Send reset (WhatsApp) or /reset (CLI) to start a new conversation.

Notes

• Flights are searched with adults=1 so the price is clearly per person; the planner multiplies by group size.
• Goa is searched as GOI,GOX in one request, covering both airports.
• Google Flights only shows return legs after you pick an outbound, so the itinerary makes one extra search (departure_token) for the chosen option.
• Booking is a demo booking by default (BOOKING_PROVIDER=simulated): it returns a reference like TP-7K3QX9 with no real ticket or payment. Real flight-booking APIs need business accreditation (Duffel doesn't accept India-registered accounts, and Amadeus closed its self-service portal in July 2026). A Duffel test-mode integration is already in tools/booking.py; set BOOKING_PROVIDER=duffel and a duffel_test_... key to use it.