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letsfg

❖ Communityv1.0.0★ 2.1k

Tools · by LetsFG · added

Search and book real flights and hotels through the hosted LetsFG MCP server (Streamable HTTP, OAuth 2.1 + DCR), with the letsfg travel-booking workflow skill bundled: fares across airlines and the major travel sites, flexible dates, destinations in a region, bookable hotel rates, then book, follow and stop bookings. Portable Agent Plugins v1 package (mcp.json + skills/).

Open in Hermes Desktop
hermes plugins install letsfg
Repository ↗Reviewed source @ 3a309f6 ↗Documentation ↗

README

From the reviewed commit 3a309f6 ↗; it updates when the author re-pins.

LetsFG plugin for Hermes Agent

LetsFG

Search and book real flights and hotels from inside Hermes Agent. Ask for the cheapest way to London next Friday, a round trip with open dates, where you could fly in Europe on a long weekend, or a hotel with breakfast near the old town. Then book it without leaving the chat.

LetsFG searches every airline and the major travel sites in one go, and books the flight or room for you on your LetsFG account.

One install ships:

  • The hosted LetsFG MCP server (letsfg) at https://letsfg.co/mcp, over Streamable HTTP.
  • skills/letsfg/, the workflow skill: how the search, shortlist and booking tools fit together, how to show LetsFG's result cards in a text chat, and the rules that keep a booking safe (book only what the traveller chose, one booking per trip, card details never in the chat).

Install

hermes plugins install letsfg          # from the Hermes plugin catalog
hermes plugins enable letsfg

Before the catalog listing is live, install straight from GitHub instead:

hermes plugins install LetsFG/LetsFG/integrations/hermes --no-enable
hermes plugins enable letsfg

Sign in (once)

LetsFG signs in with OAuth 2.1 and Dynamic Client Registration. There is no API key, and nothing secret lives in this repository. The Agent Plugins v1 mcp.json format has no field for OAuth, so tell Hermes once that this server signs in with OAuth:

hermes mcp add letsfg --url https://letsfg.co/mcp --auth oauth --connect-timeout 300

Hermes prints a letsfg.co link (and opens it when it can): approve access there. Choose Connect as a guest to start fresh, or I've connected before to sign in by e-mail and bring your saved card, travellers and preferences. No card is needed to sign in. --connect-timeout 300 gives you five minutes for that; without it, hermes mcp add gives up after 30 seconds, which is too short for the e-mail sign-in.

Hermes then lists the LetsFG tools and asks Enable all N tools? [Y/n/select]. Y is fine. Three of them (booking_setup, get_flight_search_status, get_hotel_search_status) exist only for LetsFG's in-app cards in clients such as claude.ai and ChatGPT, and the skill tells Hermes to leave them alone; to leave them out entirely, answer select and untick them.

Start a new Hermes session afterwards. Tokens are cached under ~/.hermes/mcp-tokens/ and refresh on their own. Your config.yaml entry and the plugin's mcp.json entry share the name letsfg, and the config entry wins; the plugin still supplies the skill. On a headless host, see Hermes' OAuth over SSH guide.

Try it

  • "Find me the cheapest flight from Warsaw to London next Friday, back Sunday."
  • "I have a week off in October. Where in Southern Europe can I fly from Berlin for a 4-night trip?"
  • "Round trip Lisbon to New York, any 7 nights in November, cheapest dates."
  • "A hotel in Paris for 12-14 November, two adults, breakfast included, under 400 EUR."
  • "Book option A for me."
  • "Never show me red-eye flights."

What happens when you book

Booking is real. Before anything is held:

  • You choose. The skill books only the offer you picked, at the price you saw.
  • You approve by e-mail. By default LetsFG e-mails you an Approve button before the first hold. You can switch this check off from that e-mail, never from the chat.
  • Your card stays out of the chat. Payment details are only ever entered on letsfg.co. A booking that needs a card answers with a link to add one.

Then the price is held on your card, not taken. LetsFG buys the ticket from the seller and captures the hold only once the airline has issued a booking reference. If the booking fails, the hold is released. A flight booking takes 4 to 11 minutes, and Hermes relays the progress as it goes. Say "stop" while it runs and it stops, unless the seller has already been paid.

Hotel bookings work the same way: the price is held and captured once the hotel confirms. A refundable rate can be cancelled from the chat until its free-cancellation date; the answer shows exactly what comes back.

The first booking for a new traveller needs the details an airline checkout asks for (name, date of birth, nationality, contact, address, passport). Hermes asks you for them in the chat. They are saved on your LetsFG account, so next time a saved traveller is booked by name.

Tools

Hermes exposes each tool as mcp__letsfg__<tool>. The server's own tool list is the source of truth; the main ones:

Area Tools Access
Flights search_flights, search_flexible_dates, get_flight_results, present_flight_options, get_flight_details, resolve_location Read
Hotels search_hotels, get_hotel_results, present_hotel_options, get_hotel_details, resolve_hotel_city Read
Destinations explore_destinations, present_destinations Read
Flight booking book_flight, answer_booking_question, stop_flight_booking Write
Flight booking status get_flight_booking Read
Hotel booking book_hotel, cancel_hotel_booking Write
Hotel booking status get_hotel_booking Read
Account get_agent_profile, get_preferences Read
Account edit_my_details, change_payment_method, add_preference, remove_preference Write

Changes to saved traveller details and to the payment method are approved from the account's e-mail, not the chat.

Privacy and security

  • Hosted-only connector: this folder is the whole plugin. It has no Python code, hooks or environment variables, and it does not update itself. Every tool call goes to https://letsfg.co/mcp over HTTPS.
  • Access is scoped to the signed-in LetsFG account. Traveller details you give for a booking are stored on that account and used to book.
  • Card details are never taken in the chat.
  • Privacy policy: https://letsfg.co/en/privacy · Terms: https://letsfg.co/en/terms

Troubleshooting

No LetsFG tools in the session. Run the sign-in command above, then start a new session. hermes mcp test letsfg should report the tools.

hermes mcp add says "non-interactive environment". It was run somewhere without a terminal (some desktop or agent-spawned shells). Answer y to save the config, then run hermes mcp login letsfg, which opens the sign-in anyway, and, if the entry was saved disabled, set enabled: true under mcp_servers.letsfg in ~/.hermes/config.yaml.

Tools fail with 401 or "unauthorized". The sign-in lapsed. Run hermes mcp login letsfg, then start a new session.

A booking asks for a card. Open the add_card_url link it gives and add the card on letsfg.co, then ask Hermes to carry on.

Other clients

The same server works in any MCP client: add https://letsfg.co/mcp as a remote (Streamable HTTP) server with OAuth. Setup for agents: https://letsfg.co/for-agents

Support

License

This folder (plugin manifests, skill and docs) is MIT licensed. The hosted LetsFG service and MCP server are separate and governed by the LetsFG terms.

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