Why We Need MCPs

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "prompts": [
      {
        "name": "flight_search_instruction",
        "title": "Flight Search Instruction",
        "description": "Guides the LLM to behave as a flight assistant and use the searchFlights tool effectively.",
        "arguments": [
          {
            "name": "userRequest",
            "description": "The user's flight search request in natural language",
            "required": true
          }
        ]
      }
    ]
  },
  "nextCursor": null
}

def call_llm(prompt):
    # Placeholder for an LLM call that returns structured data
    # e.g., returns {"origin": "NYC", "destination": "LON", "date": "2026-10-10"}
    pass

def call_api(url, params):
    # Placeholder for performing an HTTP request to a third-party API
    # Returns a parsed JSON response
    pass

def call_tool(tool_name, args):
    # Tool adapters normalize different airline APIs into a common flight schema
    if tool_name == "joyair_tool":
        response = call_api("https://www.joyair.com/api/flights", args)
        return [
            {
                "flightNumber": flight["flightNumber"],
                "origin": flight["origin"],
                "destination": flight["destination"],
                "price": flight.get("price")
            } for flight in response["flights"]
        ]

    elif tool_name == "dracair_tool":
        response = call_api("https://www.dracair.com/api/flights-list", args)
        return [
            {
                "flightNumber": flight["flightNum"],
                "origin": flight["from"],
                "destination": flight["to"],
                "price": flight.get("fare")
            } for flight in response["flight-info"]
        ]

    elif tool_name == "aerogo_tool":
        response = call_api("https://www.aerogo.com/api/list-flights", args)
        return [
            {
                "flightNumber": flight["flight"],
                "origin": flight["start"],
                "destination": flight["finish"],
                "price": flight.get("cost")
            } for flight in response["detail-flights"]
        ]

    else:
        raise ValueError("Unknown tool: " + tool_name)

def fetch_flight_details(origin, destination, date):
    # Aggregate results from multiple airline tools
    flights = []

    joyair_result = call_tool("joyair_tool", {"origin": origin, "destination": destination, "date": date})
    flights.extend(joyair_result)

    dracair_result = call_tool("dracair_tool", {"origin": origin, "destination": destination, "date": date})
    flights.extend(dracair_result)

    aerogo_result = call_tool("aerogo_tool", {"origin": origin, "destination": destination, "date": date})
    flights.extend(aerogo_result)

    return flights

def fetch_user_preferences(user_id):
    # Placeholder for DB/memory fetch
    return {"preference": "cheap", "seat": "aisle"}

def book_flight(flight):
    # Placeholder for booking API call
    return f"Flight {flight['flightNumber']} booking confirmed!"

# Main flow
user_input = input("Where do you want to fly?\n")

# Ask LLM to extract origin, destination, date
prompt = [
    {"role": "system", "content": "Extract origin, destination, and date from the user request."},
    {"role": "user", "content": user_input}
]
flight_query = call_llm(prompt)  # e.g., {"origin": "NYC", "destination": "LON", "date": "2026-10-10"}

origin = flight_query.get("origin")
destination = flight_query.get("destination")
date = flight_query.get("date")

flight_options = fetch_flight_details(origin, destination, date)
user_prefs = fetch_user_preferences(user_id="user-123")

# Ask LLM to pick the best flight given user preferences
decision_prompt = [
    {"role": "system", "content": f"User preferences: {user_prefs}"},
    {"role": "user", "content": f"Available flights: {flight_options}"}
]
decision = call_llm(decision_prompt)  # e.g., returns chosen flight identifier or flight dict

# Book the chosen flight (mock)
chosen = decision.get("chosen_flight") if isinstance(decision, dict) else flight_options[0]
print(book_flight(chosen))