Timetable Api Node MCP Server

Timetable API Node

Express-based API for Lviv transport timetable data with a read-only MCP endpoint.

Requirements

• Node.js 22 (see .nvmrc)

Run locally

nvm use
make start

Test

nvm use && make test

MCP Server

This service exposes a public read-only MCP endpoint over Streamable HTTP.

• MCP endpoint: /mcp
• Server card: /.well-known/mcp/server-card.json
• Discovery hint: /robots.txt (non-standard comment hint)

Production deployment (see cloudbuild.yaml for Cloud Run) serves REST and MCP from api.lad.lviv.ua. The main site lad.lviv.ua is the public transport website (this repo still links there in HTML sitemap and tables for people, not for the API host). Use your own origin when running locally.

LLM and /mcp flow

An MCP client (Claude, Cursor, or the MCP SDK) talks JSON-RPC over Streamable HTTP to POST /mcp. Tool handlers reuse the same Express actions as the REST API, backed by LokiJS timetable data, GTFS SQLite (via gtfs), and live GTFS-RT feeds (for example track.ua-gis.com).

graph LR;
  Client[LLM or MCP client] -->|JSON-RPC Streamable HTTP| Mcp["POST /mcp"];
  Mcp --> Tools[Tool handlers];
  Tools --> Actions[Express actions];
  Actions --> Loki[(LokiJS)];
  Actions --> Gtfs[(GTFS SQLite)];
  Actions --> Rt[GTFS-RT upstream];
  Loki --> Actions;
  Gtfs --> Actions;
  Rt --> Actions;
  Actions --> Tools;
  Tools --> Mcp;
  Mcp -->|MCP tool result| Client;

Try the live API

MCP Inspector (local): run npx @modelcontextprotocol/inspector, then open the UI with transport and server URL prefilled (from the inspector README):

http://localhost:6274/?transport=streamable-http&serverUrl=https%3A%2F%2Fapi.lad.lviv.ua%2Fmcp

POST https://api.lad.lviv.ua/mcp with Content-Type: application/json. The Streamable HTTP transport may require additional headers your MCP client sets automatically; for a quick manual test, follow the same sequence your MCP SDK uses (session initialize, then tools/call). Example tools/call body shape:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_stop_realtime",
    "arguments": { "stop_id": 101 }
  }
}

Successful tool responses return stringified JSON inside MCP content items (type: "text"), and each payload follows a strict UI contract:

{
  "view": "transit_realtime",
  "data": { "...": "tool-specific source data" },
  "ui_blocks": [
    { "type": "map", "data": { "...": "map renderer input" } },
    { "type": "arrival_list", "data": { "...": "arrival list renderer input" } }
  ]
}

Consistency rule: each vehicle rendered on map must either have a matching ETA in list data or eta_status: "unassigned".

Exposed tools

• get_stop_realtime
• get_vehicles_by_stop
• get_stop_geometry
• get_stops_around_location

Arguments (JSON):

Example result (shape only; values from upstream):

{
  "view": "transit_realtime",
  "data": {
    "stop": { "id": "707", "name": "Стадіон Сільмаш", "lat": 49.84, "lng": 24.03 },
    "arrivals": [
      {
        "route": "T30",
        "direction": "Рясівська",
        "vehicle_type": "tram",
        "arrival_minutes": 4,
        "vehicle_id": "tram_123",
        "lat": 49.83,
        "lng": 24.02,
        "bearing": 120
      }
    ],
    "updated_at": "2026-01-23T12:00:00Z"
  },
  "ui_blocks": [
    {
      "type": "map",
      "data": { "center": [49.84, 24.03], "vehicles": [] }
    },
    {
      "type": "arrival_list",
      "data": { "arrivals": [] }
    }
  ]
}

Arguments:

Example result:

{
  "view": "transit_realtime",
  "data": {
    "stop_ids": ["707"],
    "stops": [{ "id": "707", "name": "Стадіон Сільмаш", "lat": 49.84, "lng": 24.03 }],
    "vehicles": [
      {
        "id": "tram_123",
        "route": "T30",
        "lat": 49.83,
        "lng": 24.02,
        "bearing": 120,
        "next_stop_id": "707",
        "eta_minutes": 4,
        "eta_status": "assigned"
      }
    ]
  },
  "ui_blocks": [{ "type": "map", "data": { "vehicles": [] } }]
}

Arguments:

Example result:

{
  "view": "transit_realtime",
  "data": {
    "stop": { "id": "707", "name": "Стадіон Сільмаш", "lat": 49.84, "lng": 24.03 },
    "routes": [
      {
        "route": "T30",
        "polyline": [[49.84, 24.03], [49.83, 24.02]]
      }
    ]
  },
  "ui_blocks": [{ "type": "map", "data": { "routes": [] } }]
}

Returns stops near a map point (numeric code, name, coordinates, distance). Intended for hosts that render map UI blocks (for example ChatGPT): one block with multiple stop markers and the search center. Uses the same backend as GET /closest (see below).

Arguments (JSON):

Example result (shape only):

{
  "view": "transit_realtime",
  "data": {
    "center_lat": 49.84,
    "center_lng": 24.03,
    "radius_meters": 1000,
    "stops": [
      {
        "id": "707",
        "name": "Стадіон Сільмаш",
        "lat": 49.841,
        "lng": 24.031,
        "distance_meters": 120
      }
    ],
    "updated_at": "2026-01-23T12:00:00Z"
  },
  "ui_blocks": [
    {
      "type": "map",
      "data": {
        "center": [49.84, 24.03],
        "zoom": 15,
        "stops": [
          {
            "id": "707",
            "name": "Стадіон Сільмаш",
            "lat": 49.841,
            "lng": 24.031,
            "distance_meters": 120
          }
        ],
        "vehicles": []
      }
    }
  ]
}

Map zoom is 15 for radius ≤ 1500 m and 14 for larger radii (up to 3000 m).

Nearby stops over REST (GET /closest)

Same stop search as get_stops_around_location, for non-MCP clients:

• URL: GET /closest?latitude={lat}&longitude={lng}
• Optional: radius — meters, clamped between 50 and 3000 (default 1000).
• Response: JSON array of { code, name, latitude, longitude, distance_meters } (sorted by distance).

Security model

• Public read-only (no authentication).
• No mutating tools are exposed.
• robots.txt is only a best-effort discovery hint and not a protocol contract.