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.