google-flights-mcp

MCP server for searching Google Flights prices and schedules from Claude.

Two interchangeable data sources behind one interface (google_flights_mcp/providers/base.py):

• fast-flights (default) — scrapes Google Flights' internal protobuf search API directly. No API key, works out of the box.

• SerpApi — used automatically when a SERPAPI_KEY environment variable is set. Adds flight numbers, layover detail, and carbon emissions.

Tools

• search_flights — origin (default LIS), destination, departure_date, optional return_date, passenger counts, cabin_class, currency (default EUR), max_stops, sort_by. Returns a price-ranked list: price, airline(s), departure/arrival times, duration, stops, and a Google Flights link.

• cheapest_dates — cheapest day(s) to fly in a date window (max 21 days), price-calendar style. Runs one search per day — see "Known limitations" below.

• airport_search — resolve a city or airport name ("Lisbon") to an IATA code (LIS), backed by the offline airportsdata package.

Related MCP server: Google Flights MCP Server

Known limitations

• Round trips: for return_date searches, both providers return outbound flight options annotated with an estimated round-trip total price (paired with the cheapest matching return) — not a separately priced return leg. stops/duration/legs describe the outbound flight only. Open the result's booking_link on Google Flights to pick the exact return.

• cheapest_dates: neither fast-flights nor SerpApi's Google Flights engine expose a real bulk price-calendar endpoint, so this runs one search_flights call per candidate day. Capped at a 21-day window to keep that bounded.

• EU/UK cookie-consent wall: Google shows a cookie-consent interstitial to requests from those regions before returning real results. The fast-flights provider detects this and auto-submits "Reject all" (the privacy-preserving option) before retrying — see providers/fast_flights_provider.py if this ever needs updating for a change on Google's side.

Install

Requires Python 3.11+ and uv.

git clone https://github.com/ThiagoJacobLannes/google-flights-mcp
cd google-flights-mcp
uv sync --extra dev

On Windows, if you keep code in a cloud-synced folder (Google Drive, OneDrive), create the venv outside it — sync clients drop desktop.ini marker files into folders, which can crash packages on startup:

uv venv C:\dev\google-flights-mcp-venv
uv pip install --python C:\dev\google-flights-mcp-venv -e ".[dev]"

The command paths below assume that venv location; adjust to wherever yours lives.

Add to Claude Desktop

Merge claude_desktop_config.snippet.json into your Claude Desktop config (%APPDATA%\Claude\claude_desktop_config.json):

{
  "mcpServers": {
    "google-flights": {
      "command": "C:\\dev\\google-flights-mcp-venv\\Scripts\\python.exe",
      "args": ["-m", "google_flights_mcp.server"]
    }
  }
}

Restart Claude Desktop after editing. To use SerpApi instead of the default scraper, add an env block:

{
  "mcpServers": {
    "google-flights": {
      "command": "C:\\dev\\google-flights-mcp-venv\\Scripts\\python.exe",
      "args": ["-m", "google_flights_mcp.server"],
      "env": { "SERPAPI_KEY": "your-serpapi-key" }
    }
  }
}

Get a key at serpapi.com (free tier available).

Other env vars: GOOGLE_FLIGHTS_DEFAULT_ORIGIN (default LIS), GOOGLE_FLIGHTS_DEFAULT_CURRENCY (default EUR).

Running over HTTP (for a remote connector)

C:\dev\google-flights-mcp-venv\Scripts\python.exe -m google_flights_mcp.server --http

Or set MCP_TRANSPORT=streamable-http. Configure the bind address with MCP_HOST (default 127.0.0.1) and MCP_PORT (default 8000); the server listens at http://<host>:<port>/mcp. Put this behind whatever reverse proxy / auth you use for your other remote connectors before exposing it beyond localhost.

Smoke test

Real network call (no mocks) — searches LIS → GRU about a month out:

C:\dev\google-flights-mcp-venv\Scripts\python.exe tools\google-flights-mcp\examples\smoke_test.py

Tests

C:\dev\google-flights-mcp-venv\Scripts\python.exe -m pytest tools\google-flights-mcp\tests

These are unit tests against the provider abstraction (factory selection, passenger validation, the shared cheapest_dates day-loop, airport resolution) — no network access required.