G-Guest MCP server

Book a table, an appointment or a place in a class at a real local business, from an AI assistant, with no API key and no account.

G-Guest is the booking system those businesses run on. This server exposes it to assistants over MCP: find a venue, read its real availability, and create a booking that is confirmed instantly and appears in the venue's own panel.

Endpoint · https://g-guest.app/api/mcp Transport · streamable HTTP (JSON-RPC 2.0 over POST) Auth · none. Reading and booking are open; a booking must carry the guest's name, phone and email.

Tools

Exact schemas: tools.json, generated from the live endpoint, not written by hand.

Guest languages

The booking page, the confirmation, the reminders and the manage page speak the guest's language. Pass it on create_booking as language (ISO 639-1): en, nl, de, fr, es, it, id or bg. Defaults to English. The venue's own words (its name, dishes, class names) are never translated.

Two ways to connect

By URL, if your client speaks streamable HTTP. Point it at https://g-guest.app/api/mcp. Nothing to install.

By command, if your client expects a local stdio server, which is what Claude Desktop and Cursor configs usually want:

{
  "mcpServers": {
    "g-guest": {
      "command": "npx",
      "args": ["-y", "g-guest-mcp"]
    }
  }
}

That command runs the small proxy in this repository. It forwards every call to the hosted endpoint and hands the answer back unchanged: no booking logic runs on your machine, and no key is needed. GGUEST_MCP_URL overrides the endpoint if you are pointing at something else.

The tool list is not written into the proxy. It asks the live server for it at start-up, so the wrapper cannot fall behind the service; with no network it falls back to the tools.json in this repository, which is generated from that same endpoint.

Try it without installing anything

curl -s -X POST https://g-guest.app/api/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

A live demo venue is demo-studio (a pilates studio) and demo (a restaurant). Booking against those is real but harmless: they are ours.

Adding it to an assistant

• Claude, Codex, and custom agents: point them at the endpoint. Nothing to install.
• ChatGPT: add it as a connector (developer mode). Step-by-step, with what we have actually tested and what we have not: https://g-guest.app/ai

Honesty about what this is

Every venue reachable here is a paying or trialling customer of G-Guest, and a booking made through this server is a real reservation that a real business will honour. There is no marketplace in the middle and no commission on the booking.

We list only what we have tested ourselves. https://g-guest.app/ai says which assistants have actually created a confirmed booking here, and on what date.

Where the code lives

The booking engine is not here and never will be. Availability, slot arithmetic, the guest list, everything that decides whether a table can be sold: that lives inside the G-Guest application and stays there.

What this repository does hold is the stdio proxy in src/, about a hundred lines whose entire job is to pass JSON-RPC through and return the reply as it came. It exists because a good half of the clients and directories expect a command to run rather than a URL to call, and because a sandbox has to be able to build and introspect the server without reaching our infrastructure.

tools.json is regenerated from the live endpoint. If the two ever disagree, the live endpoint is right.

Links

• Service manifest · https://g-guest.app/.well-known/g-guest.json
• OpenAPI (plain HTTP, for agents without MCP) · https://g-guest.app/openapi.json
• What works today, per assistant · https://g-guest.app/ai
• G-Guest · https://g-guest.app

Made by G-Lab Studio.