Configuration

The MCP server can be customized using environment variables. All configuration is optional and has sensible defaults.

Environment variables

All configuration variables use the FLI_MCP_ prefix.

FLI_MCP_DEFAULT_PASSENGERS

integer

default:"1"

Default number of adult passengers for searches. Must be at least 1.

FLI_MCP_DEFAULT_PASSENGERS=2

FLI_MCP_DEFAULT_CURRENCY

string

default:"USD"

Three-letter currency code returned with search results. Must be exactly 3 characters.

FLI_MCP_DEFAULT_CURRENCY=EUR

FLI_MCP_DEFAULT_CABIN_CLASS

string

default:"ECONOMY"

Default cabin class when none is specified. Options:

ECONOMY
PREMIUM_ECONOMY
BUSINESS
FIRST

FLI_MCP_DEFAULT_CABIN_CLASS=BUSINESS

FLI_MCP_DEFAULT_SORT_BY

string

default:"CHEAPEST"

Default sorting strategy for flight results. Options:

CHEAPEST - Sort by lowest price
DURATION - Sort by shortest flight time
DEPARTURE_TIME - Sort by earliest departure
ARRIVAL_TIME - Sort by earliest arrival

FLI_MCP_DEFAULT_SORT_BY=DURATION

FLI_MCP_DEFAULT_DEPARTURE_WINDOW

string

Default departure time window in ‘HH-HH’ 24-hour format. If not set, no time restriction is applied.

FLI_MCP_DEFAULT_DEPARTURE_WINDOW=6-20  # 6am to 8pm

FLI_MCP_MAX_RESULTS

integer

Maximum number of results returned by each tool. Must be greater than 0. If not set, all results are returned.

FLI_MCP_MAX_RESULTS=10

Configuration with Claude Desktop

Set environment variables in your Claude Desktop configuration file:

{
  "mcpServers": {
    "fli": {
      "command": "fli-mcp",
      "args": [],
      "env": {
        "FLI_MCP_DEFAULT_CURRENCY": "EUR",
        "FLI_MCP_DEFAULT_CABIN_CLASS": "BUSINESS",
        "FLI_MCP_DEFAULT_SORT_BY": "DURATION",
        "FLI_MCP_DEFAULT_DEPARTURE_WINDOW": "8-22",
        "FLI_MCP_MAX_RESULTS": "10"
      }
    }
  }
}

Configuration file locations

macOS:

~/Library/Application Support/Claude/claude_desktop_config.json

Windows:

%APPDATA%\Claude\claude_desktop_config.json

Linux:

~/.config/Claude/claude_desktop_config.json

Configuration examples

European traveler

Configure for Euro currency and preferred departure times:

{
  "mcpServers": {
    "fli": {
      "command": "fli-mcp",
      "args": [],
      "env": {
        "FLI_MCP_DEFAULT_CURRENCY": "EUR",
        "FLI_MCP_DEFAULT_DEPARTURE_WINDOW": "9-18"
      }
    }
  }
}

Business traveler

Configure for business class and minimal results:

{
  "mcpServers": {
    "fli": {
      "command": "fli-mcp",
      "args": [],
      "env": {
        "FLI_MCP_DEFAULT_CABIN_CLASS": "BUSINESS",
        "FLI_MCP_DEFAULT_SORT_BY": "DEPARTURE_TIME",
        "FLI_MCP_MAX_RESULTS": "5"
      }
    }
  }
}

Family travel

Configure for multiple passengers:

{
  "mcpServers": {
    "fli": {
      "command": "fli-mcp",
      "args": [],
      "env": {
        "FLI_MCP_DEFAULT_PASSENGERS": "4",
        "FLI_MCP_DEFAULT_SORT_BY": "CHEAPEST"
      }
    }
  }
}

Budget traveler

Focus on cheapest options with limited results:

{
  "mcpServers": {
    "fli": {
      "command": "fli-mcp",
      "args": [],
      "env": {
        "FLI_MCP_DEFAULT_SORT_BY": "CHEAPEST",
        "FLI_MCP_MAX_RESULTS": "3"
      }
    }
  }
}

FlightSearchConfig class

The configuration is implemented using the FlightSearchConfig Pydantic settings class in fli/mcp/server.py:51. This class:

Automatically loads environment variables with the FLI_MCP_ prefix
Validates all configuration values
Provides type safety for configuration options
Exposes defaults through the MCP resource endpoint

Configuration schema

The server exposes its configuration schema through an MCP resource. AI assistants can query this resource to understand the current configuration:

{
  "defaults": {
    "default_passengers": 1,
    "default_currency": "USD",
    "default_cabin_class": "ECONOMY",
    "default_sort_by": "CHEAPEST",
    "default_departure_window": null,
    "max_results": null
  },
  "schema": {
    "properties": {
      "default_passengers": {
        "type": "integer",
        "minimum": 1,
        "description": "Default number of adult passengers to include in searches."
      },
      "default_currency": {
        "type": "string",
        "minLength": 3,
        "maxLength": 3,
        "description": "Three-letter currency code returned with search results."
      }
    }
  }
}

Applying configuration changes

After modifying environment variables:

Save the configuration file
Completely quit Claude Desktop (not just close the window)
Restart Claude Desktop
The new configuration will be loaded automatically

Validating configuration

You can verify your configuration by asking Claude:

What is your current Fli configuration?

Claude can access the configuration resource to show you the active settings.

Next steps

Tool reference

Learn about search parameters and options

Setup guide

Initial installation and configuration

Get Started

MCP Server

CLI Usage

Python Library

Guides

Configuration

Environment variables

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

Configuration with Claude Desktop

Configuration file locations

Configuration examples

FlightSearchConfig class

Configuration schema

Applying configuration changes

Validating configuration

Next steps

Tool reference

Setup guide

​Environment variables

​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

​Configuration with Claude Desktop

​Configuration file locations

​Configuration examples

​FlightSearchConfig class

​Configuration schema

​Applying configuration changes

​Validating configuration

​Next steps

Tool reference

Setup guide

Environment variables

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

Configuration with Claude Desktop

Configuration file locations

Configuration examples

FlightSearchConfig class

Configuration schema

Applying configuration changes

Validating configuration

Next steps