Google Flights CLI and MCP

Guidance for installing and using Fli correctly as a CLI and MCP server. Use when: setting up Fli with pipx, running fli flight searches, configuring Claude Desktop with fli-mcp, using the HTTP MCP server, or troubleshooting Fli command availability and common usage mistakes.

Fli install and usage skill

Use this skill when the goal is to install Fli and use its CLI or MCP server correctly.

The primary path is:

1. install with pipx install flights
2. use fli for terminal searches
3. use fli-mcp for Claude Desktop or other STDIO MCP clients
4. use fli-mcp-http only when an HTTP MCP endpoint is specifically needed

Do not default to cloning the repository or using a source checkout. Only mention cloning the repo when the user explicitly wants to contribute to Fli itself.

What Fli is

Fli is a Python package for accessing Google Flights data through direct API interaction.

It has three public surfaces:

• CLI via fli
• Python library via the fli package
• MCP server via fli-mcp and fli-mcp-http

For this skill, focus on the CLI and MCP server first.

Core install rule

If the user wants to use Fli as a tool, recommend pipx install flights.

Why:

• it is the documented recommended install path for CLI and MCP usage
• it keeps the install isolated from other Python projects
• it exposes fli, fli-mcp, and fli-mcp-http on the user's PATH

Only fall back to pip install flights or uvx when:

• pipx is unavailable
• the user wants library-only usage
• the user explicitly prefers another Python package manager

Standard installation flow

Preferred install

bash

python3 -m pip install --user pipx
python3 -m pipx ensurepath
pipx install flights

If pipx is already installed, skip directly to:

bash

pipx install flights

Verify installation

Run these checks after install:

bash

fli --help
fli-mcp --help
which fli-mcp

If the commands are not found after pipx install flights, have the user run:

bash

python3 -m pipx ensurepath

Then restart the terminal session.

What the install provides

After pipx install flights, these commands should be available:

• fli - main CLI for flight searches
• fli-mcp - MCP server over STDIO
• fli-mcp-http - MCP server over HTTP, defaulting to http://127.0.0.1:8000/mcp/

Important naming detail:

• the package to install is flights
• the commands to run are fli, fli-mcp, and fli-mcp-http

Do not tell users to run pipx install fli.

CLI usage

Basic flight search

Use:

bash

fli flights JFK LAX 2026-10-25

Cheapest-date search

Use:

bash

fli dates JFK LAX --from 2026-01-01 --to 2026-01-31

Common filters

Use filters like these when the user asks for them:

bash

fli flights JFK LHR 2026-10-25 \
  --time 6-20 \
  --airlines BA KL \
  --class BUSINESS \
  --stops NON_STOP \
  --sort DURATION

Supported language to map correctly:

• cabin classes: ECONOMY, PREMIUM_ECONOMY, BUSINESS, FIRST
• stop filters: ANY, NON_STOP, ONE_STOP, TWO_PLUS_STOPS
• sort options: CHEAPEST, DURATION, DEPARTURE_TIME, ARRIVAL_TIME

CLI shorthand

Fli supports a convenience shorthand where a non-command invocation is treated as a flights search.

Example:

bash

fli JFK LAX 2026-05-15

This behaves like:

bash

fli flights JFK LAX 2026-05-15

Use the explicit flights subcommand in examples unless the user asks for shortcuts.

MCP usage

Default MCP mode

Use fli-mcp for Claude Desktop and other STDIO-based MCP clients.

bash

fli-mcp

This is the default recommendation for local assistant integration.

HTTP MCP mode

Use fli-mcp-http only when the user needs an HTTP endpoint.

bash

fli-mcp-http

By default, it serves at:

• http://127.0.0.1:8000/mcp/

For HTTP integrations, the client should send:

• Accept: application/json, text/event-stream

Claude Desktop setup

When the user wants Claude Desktop integration, recommend this config first:

json

{
  "mcpServers": {
    "fli": {
      "command": "fli-mcp",
      "args": []
    }
  }
}

Suggested config paths:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\\Claude\\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

After editing the config:

1. fully quit Claude Desktop
2. relaunch it
3. start a new conversation
4. ask for a flight search

Good validation prompt:

Can you search for flights from JFK to LHR on 2026-03-15?

Optional MCP environment variables

If the user wants defaults, these environment variables are relevant:

• FLI_MCP_DEFAULT_PASSENGERS
• FLI_MCP_DEFAULT_CURRENCY
• FLI_MCP_DEFAULT_CABIN_CLASS
• FLI_MCP_DEFAULT_SORT_BY
• FLI_MCP_DEFAULT_DEPARTURE_WINDOW
• FLI_MCP_MAX_RESULTS

Example:

json

{
  "mcpServers": {
    "fli": {
      "command": "fli-mcp",
      "args": [],
      "env": {
        "FLI_MCP_DEFAULT_CURRENCY": "EUR",
        "FLI_MCP_DEFAULT_CABIN_CLASS": "BUSINESS",
        "FLI_MCP_MAX_RESULTS": "10"
      }
    }
  }
}

How to guide users well

If the user asks to install Fli

Give them the pipx install flights path first.

If the user asks how to use the command line tool

Show fli flights ... and fli dates ... examples first.

If the user asks how to connect Claude or another assistant

Show fli-mcp and the Claude Desktop config first.

If the user asks for a web endpoint

Then show fli-mcp-http and mention the /mcp/ path and Accept header.

If the user asks how to contribute or hack on the codebase

That is outside the primary scope of this skill. Only then discuss cloning the repository and using development commands.

Common mistakes to prevent

• telling users to clone the repository when they only want the tool
• telling users to install fli instead of flights
• focusing on the Python API when the user asked for CLI or MCP setup
• giving HTTP MCP instructions when STDIO MCP is enough
• forgetting to tell Claude Desktop users to fully restart the app
• omitting the PATH fix when pipx installs successfully but commands are not found

Troubleshooting

fli or fli-mcp not found

Try:

bash

python3 -m pipx ensurepath

Then restart the terminal.

Python version problems

Fli requires Python 3.10 or newer.

Check with:

bash

python3 --version

Claude Desktop does not show the tools

Check these in order:

1. fli-mcp --help works in a terminal
2. the Claude Desktop config file path is correct
3. the JSON is valid
4. Claude Desktop was fully quit and reopened

Rate limiting or temporary failures

Fli includes automatic rate limiting and retries, but live Google Flights requests can still fail temporarily.

If a query fails:

• retry after a short delay
• reduce repeated back-to-back searches
• do not assume the CLI or MCP setup is broken just because one upstream request failed

Public docs

Use these docs for product-facing guidance:

• introduction: https://punitarani-fli.mintlify.app/introduction
• installation: https://punitarani-fli.mintlify.app/installation
• MCP setup: https://punitarani-fli.mintlify.app/mcp/setup
• docs index: https://punitarani-fli.mintlify.app/llms.txt

Use product docs for examples and onboarding. Use the actual installed command names when writing instructions.

Summary

The default recommendation is pipx install flights. After that, use fli for terminal searches, fli-mcp for Claude Desktop and other STDIO MCP clients, and fli-mcp-http only when an HTTP MCP endpoint is specifically needed.