Airfare Brain

com.airfarebrainPublished by airfarebrain.comOfficial publisherv1.0.6Updated Oct 29, 2026

True cost of flight extras (bags, seats, fees) on 29 airlines in Europe and North America, sourced.

VerifiedStreamable HTTPWeb executableLocation & Lifestyle Finance

Server details

Identifier: com.airfarebrain/airfare-brain
Transport: Streamable HTTP
Runtime: Web executable
Trust: Verified
Published: Oct 20, 2026

Security note

MCP servers receive tool arguments from a conversation and may perform external actions. Review what a server can do before you enable it, and give it only the access it needs.

The registry verified that this server's namespace belongs to airfarebrain.com, which also runs its endpoint. That identifies the publisher; it does not make the server's tools safe.

SourceWeft's checks cover whether the listing is complete and the endpoint answered; they do not review the server's code or what its tools do.

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Overview

AI-generated overview

Remote MCP server that gives an assistant dated, sourced airline extra-fee data so it can estimate the true cost of a flight with bags, seats and fees.

What you can do: Describe coverage, research method and limits, and list airlines with fee tables and check dates
Look up one airline's published fees for bags, seats, priority, check-in, changes and payment, with price ranges, source and date
Calculate fare plus chosen extras for a party and trip, including what extras cost if added later or at the airport
Combine an airline's extras with measured car-hire costs for a specific arrival airport
When to use it: Useful when someone has a fare from a flight search and wants to know what bags, seats and fees add, or when comparing low-cost and full-service options where the cheapest fare may not be the cheapest trip.
Requirements: Remote streamable HTTP endpoint; no API key, login or account. Stdio-only clients need a bridge such as npx mcp-remote. Network access required.

Before you install

It has no live fares and does not book; figures are published ranges, not quotes, so the airline page should be checked. Fee data is read-only and takes no personal data. The website's flight search uses Kiwi.com affiliate links, though the MCP tools return fee data only.

Installation

In SourceWeft

Open Airfare Brain in the dashboard and add it to a workspace.
Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/com.airfarebrain%2Fairfare-brain/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "airfare-brain": {
      "type": "http",
      "url": "https://airfarebrain.com/mcp"
    }
  }
}

README

[Airfare Brain]

Airfare Brain MCP server

The true cost of a flight, for AI assistants. Bags, seats, priority boarding, check-in and payment fees on 32 airlines (Ryanair, easyJet, Wizz Air, Jet2, British Airways, Lufthansa, KLM, Air France, Iberia, Turkish, Finnair, SAS, Swiss, Austrian, Delta, United, Southwest, JetBlue and more), each price taken from the airline's own pages, with the source and the date it was checked.

Free. No API key. No login. Read-only.

MCP endpoint (streamable HTTP):

Listed in the official MCP Registry as com.airfarebrain/airfare-brain. Website: airfarebrain.com · Fee data: airfarebrain.com/fees · For AI: llms.txt

Why it exists

The fare a flight search shows is not what the trip costs. A cabin bag, a checked bag, a seat next to someone you know, checking in at the airport or paying by card can each add more than the fare itself, and the price goes up if you add them later or at the airport. Airfare Brain reads each airline's published fee pages, records every price with its source and date, and answers with the numbers, so an assistant can say what a flight will really cost.

Tools

Tool	What it answers
`get_capabilities`	What is covered, how fees are researched and dated, what it does not do (no live fares, no booking)
`list_airlines`	Every airline with a fee table: name, IATA code, the date its fees were checked, its page
`airline_fees`	One airline's extras (bags, seats, priority, check-in, changes, payment): price range, when bought (at booking / later / at the airport), source URL, date checked
`true_cost`	Fare + the extras the person chooses, for the whole party and each flight, with what it costs if added later or at the airport
`trip_at_airport`	The whole trip into one airport: the flight's extras on an airline AND what car hire there really costs (Car Rental Brain's measured median per day), dated and linked

Ranges are shown exactly as the airline publishes them. A fee the airline does not publish is said to be unknown, never counted as free. Figures from a third party (only where the airline publishes none) are labelled "reported".

Example questions

"I found a Ryanair flight for €39. What will it cost with a cabin bag and a 20kg bag, return?"
"Is easyJet or Wizz Air cheaper for two people with one checked bag between them?"
"What does Jet2 charge to choose a seat?"
"How much more is a bag at the airport than online on Wizz Air?"
"Does British Airways' Basic fare include a cabin bag?"
"Flying Ryanair into Malaga for a week with a 20kg bag and a hire car: what will it all cost?"

Connect

Claude (claude.ai / Claude Desktop)

Settings → Connectors → Add custom connector → URL https://airfarebrain.com/mcp.

Or in claude_desktop_config.json:

Claude Code (plugin)

/plugin marketplace add jimiwalters-cmyk/airfare-brain-mcp/plugin install airfare-brain@airfare-brain

/plugin marketplace add jimiwalters-cmyk/airfare-brain-mcp/plugin install airfare-brain@airfare-brain

Or add the server directly: claude mcp add --transport http airfare-brain https://airfarebrain.com/mcp

ChatGPT

Settings → Apps & Connectors → Advanced → Developer mode → Create → MCP server URL https://airfarebrain.com/mcp, authentication: none.

Cursor / Windsurf / Cline / VS Code

Stdio-only clients

Plain JSON

All fee tables in one file: airfarebrain.com/data/fees.json.

How the numbers are made

Each airline's fee pages are read by hand, every value is stored with the page it came from, a short quote and the date, and each table is re-checked monthly (a table past its re-check date is flagged on the site). Travellers can report what they actually paid; those reports are checked against the tables.

Fee pages

The same data as web pages, one per airline (checked bag, cabin bag, seats, with the date and the airline's own source):

Aer Lingus · Air Canada · Air France · Alaska Airlines · American Airlines · Austrian Airlines · British Airways · Delta Air Lines · easyJet · Eurowings · Finnair · Frontier Airlines · Iberia · Jet2 · JetBlue · KLM · Lufthansa · Norwegian · Pegasus · Ryanair · SAS · Southwest Airlines · Swiss · TAP Air Portugal · Transavia · Turkish Airlines · United Airlines · Virgin Atlantic · Volotea · Vueling · WestJet · Wizz Air

Compare all airlines: checked bags · cabin bags · seats. Booking through Kiwi.com: what it adds to bag prices. Flights into 124 airports with the true cost and car hire there.

Sister tool

For car hire at the airport you land at: Car Rental Brain (https://app.carrentalbrain.com/mcp).

Affiliate disclosure

The MCP tools return fee data only, with no booking links. The airfarebrain.com website's flight search links to Kiwi.com through its affiliate programme, and Airfare Brain may earn a small commission at no cost to the person booking.

Privacy

The tools take no personal data and need no account. Privacy policy: airfarebrain.com/privacy.

Contact

[email protected]

Source: README.md at commit 301b4c5

Tools

get_capabilities

Get capabilities

What Airfare Brain covers: airlines, how fees are researched and dated, what it does NOT do (no live fares, no booking), and what car hire at the destination airport typically costs.

Takes no parameters.

list_airlines

List airlines

List every airline with a fee table: name, IATA code, the date its fees were checked, and its page.

Takes no parameters.

airline_fees

Airline fees

One airline's published extra fees (bags, seats, priority, check-in, changes, payment), each with the price range, when bought (at booking / later / airport), how it is charged, its source URL and the date checked. Optionally filter by category.

Parametersairlinerequiredcategorycurrency

true_cost

True cost

The true cost of a flight on one airline. Pass `fare` (the total for the whole party, from a flight-search tool or the person) to get fare + extras; without it you get the extras alone. Extras = what the person chooses (cabin bag, checked bag by kg, seat, priority, infants) for their party and trip, as the range the airline publishes. Also lists what costs more if left until the airport, unchosen fees that may apply (admin, card %), and extras the airline does not publish a price for.

Parametersfareseattripairlinerequiredinfantscurrencydomesticprioritycabin_baghold_bagsgroup_bagspassengers+1 more

trip_at_airport

Trip at airport

The whole trip into one airport in one answer: the flight's extras on an airline (bags, seats, fees, as true_cost) AND what car hire there really costs (Car Rental Brain's measured median per day, car only, dated). Use for 'flying to Faro with Ryanair, bags and a hire car: what will it cost?'. Car only: deposits, second-driver fees and desk cover are not included; the answer links to the airport's full car-hire report.

Parametersfareseattripairlineairportrequiredinfantscar_dayscurrencydomesticprioritycabin_baghold_bags+3 more

Version history

v1.0.6LatestOct 29, 2026
v1.0.5Oct 25, 2026
v1.0.4Oct 25, 2026
v1.0.3Oct 24, 2026
v1.0.2Oct 23, 2026
v1.0.1Oct 22, 2026
v1.0.0Oct 20, 2026

Score

100% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

Reached in the last 30 daysRequired25 pts
Auth declaredRequired10 pts
Tools listedRequired15 pts
DescriptionRequired15 pts
Logo10 pts
Documentation15 pts
License10 pts