Lviv Public Transport

Timetable API Node

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

Requirements

• Node.js 26 (see .nvmrc)

Run locally

nvm use

npm install cp .env.dist .env make import # first run, and whenever the GTFS feed changes make start

make import downloads the static GTFS feed (gtfs-import-config.json) and writes the two stores the server reads: database/Timetable (LokiJS: stops, routes, shapes, first-stop schedules) and database/gtfs (SQLite: trips and calendars). Both are gitignored, so a fresh clone has no data until it runs. make import-slim re-imports only the light tables into SQLite and leaves database/Timetable alone.

Configuration

All variables are optional; see .env.dist.

Test

nvm use && make test

TypeScript

The code is TypeScript and runs straight from the .ts sources under Node's built-in type stripping — there is no build step for the server, the GTFS import or the scripts. That means only erasable syntax (no enum, namespace or parameter properties), import type for type-only imports, and relative imports that name the .ts file; tsconfig.json enforces all three.

npm run typecheck   # tsc, no emit

npm run build emits just mcp/stdio.js, the published bin: Node does not strip types inside node_modules, so the npm package has to ship JavaScript. It runs on npm pack/npm publish; the output is not committed.

public/stopOverrides.js is served to browsers as-is, so it stays JavaScript and is type-checked from its JSDoc.

Monitoring

New Relic APM, off unless NEW_RELIC_LICENSE_KEY is set. It also carries errors and the custom metrics recorded through utils/metrics.ts.

New Relic runs as a preloaded agent, so npm start carries the flags:

node -r dotenv/config -r newrelic --import newrelic/esm-loader.mjs index.ts

dotenv/config is preloaded first so .env is populated before the agent reads its configuration. The config file is newrelic.cjs (the agent is CommonJS and this project is ESM) and holds no secrets — the key comes from the environment. /health is excluded from transactions via rules.ignore.

The account is in the EU region; its license key starts with eu01xx and the agent picks the collector from that prefix. Use the 40-character ingest license key, not an NRAK-... user API key.

Cloud Run reads the key from Secret Manager:

gcloud run services update timetable-api-node --region=europe-north1 --project=timetable-252615 --set-secrets=NEW_RELIC_LICENSE_KEY=new-relic-license-key:latest

MCP Server

This service exposes a public read-only MCP endpoint over Streamable HTTP. It speaks MCP revision 2026-07-28 (stateless: server/discover, a per-request _meta envelope, cacheable list results) and still serves 2025-era clients that open with initialize (2025-11-25 back to 2024-11-05).

• 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](https://api.lad.lviv.ua). The main site [lad.lviv.ua](https://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

Postman / curl: call a tool on production

POST https://api.lad.lviv.ua/mcp with Content-Type: application/json and Accept: application/json, text/event-stream — the Streamable HTTP transport rejects a request that does not accept both. The server is stateless: there is no session, so tools/call works on its own without an initialize first. The response arrives as a single SSE event: message frame carrying the JSON-RPC result. This is the 2025-era request shape; a 2026-07-28 request also sends MCP-Protocol-Version: 2026-07-28 and Mcp-Method headers, plus io.modelcontextprotocol/protocolVersion and io.modelcontextprotocol/clientCapabilities in params._meta.

curl -s https://api.lad.lviv.ua/mcp \

-H 'Content-Type: application/json' \ -H 'Accept: application/json, text/event-stream' \ -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"get_stop_realtime","arguments":{"stop_id":101}}}'

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 a natural-language text summary inside MCP content items (type: "text") — e.g. *"Stop «Площа Ринок»: 6 arrivals. Next: Т02 → «Пасічна» in 3 min."* The full structured payload is in the structuredContent field (for schema-aware clients). Each structuredContent payload follows one contract:

{

"view": "transit_realtime", "data": { "...": "tool-specific payload" }, "ui_blocks": [ { "type": "map", "data": { "center": [49.84, 24.03], "zoom": 14, "layers": { "stops": "data.stop", "vehicles": "data.arrivals" } } }, { "type": "arrival_list", "data": { "source": "data.arrivals" } } ] }

ui_blocks point into data instead of repeating it. A map block gives the centre and zoom, and layers maps stops, vehicles and polylines to a dot path in the result; every stop and vehicle there has lat/lng, vehicles also bearing. An arrival_list block names the arrivals array to render, already sorted by arrival_minutes (null = no ETA).

Exposed tools

All tools are read-only. Stop IDs are the numeric codes on stop signs, returned as strings ("707"). Route names are the short names on vehicles ("Т30", "А1"); Latin "T30"/"A01" work too, and a bare number is read as an internal route ID. An unknown route or vehicle returns isError: true with a hint on what to pass instead.

| get_vehicle_info | vehicle_id | One vehicle: position, route, destination, plate, upcoming stops (id, name, ISO