Onebusaway MCP Server README

Overview

Real-time transit from OneBusAway, set up for Puget Sound (King County Metro, Sound Transit, Pierce Transit, Community Transit, and more) and compatible with any OneBusAway instance. Find stops and routes, track live arrivals and vehicle positions, and pull schedules and service alerts.

Tools

Resources

The same data is available to tool-only clients through onebusaway_get_stop and onebusaway_get_route.

Capability reference

onebusaway_list_agencies _tool

• No input; returns every agency with id, contact info, timezone, and coverageCenter / coverageSpan
• limitExceeded flags an upstream-capped list, with no pagination to fetch the rest

onebusaway_find_stops _tool

• lat / lon required; radius in meters, default 300, max 1600; optional query matches the stop code printed on the sign
• Each stop carries id, code, direction, routeIds, and wheelchairBoarding (ACCESSIBLE / NOT_ACCESSIBLE / UNKNOWN); limitExceeded means more stops exist within the radius

onebusaway_search_stops _tool

• query (stop name fragment or stop code) required; maxCount up to 100, default 10
• Same stop shape as onebusaway_find_stops; limitExceeded means more stops matched than maxCount

onebusaway_get_stop _tool

• Single stopId; returns name, code, coordinates, direction, routeIds, and wheelchairBoarding
• Unknown IDs fail as stop_not_found, with recovery via onebusaway_find_stops or onebusaway_search_stops

onebusaway_find_routes _tool

• lat / lon required; radius in meters, default 500, max 1600, or a latSpan + lonSpan box (both set) in its place; optional query by route name or number
• Each route carries shortName, longName, agencyId, GTFS type (0=tram … 5=cable_car), color, and schedule url; limitExceeded means more routes exist in the area

onebusaway_search_routes _tool

• query (route name or number) required; maxCount up to 100, default 10
• Returns shortName, longName, agencyId, and GTFS type; limitExceeded means more routes matched than maxCount
• Fails as endpoint_unavailable on instances whose route-search endpoint returns 404, Puget Sound among them; use onebusaway_find_routes or onebusaway_list_routes_for_agency instead

onebusaway_get_route _tool

• Single routeId; returns shortName, longName, description, agency, GTFS type, color, and schedule url
• Unknown IDs fail as route_not_found, with recovery via onebusaway_find_routes or onebusaway_search_routes

onebusaway_list_routes_for_agency _tool

• agencyId required; unknown agencies fail as agency_not_found
• Every route with shortName, longName, GTFS type, color, and url; limitExceeded flags an upstream-capped list with no pagination

onebusaway_get_arrivals _tool

• stopId required; the window is minutesBefore (integer 0–60, default 5) / minutesAfter (integer 0–240, default 35), with longer horizons left to onebusaway_get_schedule_for_stop; unknown stops fail as stop_not_found
• Each arrival carries predicted (false = schedule-only), scheduleDeviation in seconds (positive = late, meaningful only when predicted), predictedArrivalTime, vehiclePosition, stopsAway, and tripId
• Active alerts arrive in situations[]: those on the stop itself plus those linked from each arrival's situationIds, each once

onebusaway_get_stop_context _tool

• Same input as onebusaway_get_arrivals, and the same stop_not_found / rate_limited failures; one call issues one upstream request
• Returns stop (the onebusaway_get_stop fields minus routeIds), arrivals in the onebusaway_get_arrivals shape, and alerts in the onebusaway_get_alert shape — every alert on the stop or on an arrival in the window, including stop-wide alerts no arrival in the window carries
• When the upstream response omits the stop, stop is null; a referenced alert missing from the response is left out; either way a notice names the tool to fetch it with

onebusaway_get_alert _tool

• Single situationId, from onebusaway_get_arrivals (situations[].id or arrivals[].situationIds); unknown IDs fail as situation_not_found
• Returns a TPEG reason code, severity, consequenceMessage, affects (agency, route, stop, or trip scope), consequences with diversion stop IDs, and activeWindows

onebusaway_get_trip _tool

• tripId required; serviceDateMs (non-negative integer, midnight local) only for a trip on a previous service day; includeSchedule (default true) adds the stop sequence with GTFS times and distanceAlongTripMeters
• status carries phase (e.g. in_progress, layover_before), predicted, position, scheduleDeviation, and nextStop; blockId (null when the trip has none) feeds onebusaway_get_block
• Fails as trip_not_found when the trip isn't active for the service date; a completed trip's times come from onebusaway_get_schedule_for_route

onebusaway_get_block _tool

• Single blockId, from onebusaway_get_trip; unknown IDs fail as block_not_found
• Top-level trips, activeServiceIds, and inactiveServiceIds describe the first returned configuration; alternateConfigurations preserves every remaining configuration in order. Service IDs are calendar conditions, not a claim that a configuration operates today
• Each trip carries distanceAlongBlock, accumulatedSlackTime (layover seconds), and blockStopTimes. Optional exact tripId or departureFromSec / departureBeforeSec selects complete trips independently in every configuration, retaining empty configuration slots
• With selectors, selection.total / returned count trip occurrences across configurations; configurationCounts[0] describes the top-level configuration, then one entry per alternative

Example: {"blockId":"<blockId from onebusaway_get_trip>","departureFromSec":86400,"departureBeforeSec":90000} selects trips with any departure from 24:00 inclusive to 25:00 exclusive, retaining their complete stop sequences.

onebusaway_get_vehicles _tool

• agencyId required, unknown agencies fail as agency_not_found; optional routeId is filtered client-side after all of the agency's vehicles are fetched
• Each vehicle carries position, orientation, phase, scheduleDeviation, tripId, nextStop, and predicted (reporting real-time GPS); limitExceeded flags an upstream-capped list with no pagination
• tripId prefers the active trip; route and headsign metadata resolve only from that trip. orientation preserves counter-clockwise degrees from east (0=east, 90=north, 180=west, 270=south), not a compass bearing
• Records missing latitude or longitude are skipped: omittedWithoutPosition counts them across the agency, and omittedWithoutPositionOnRoute counts resolved matches when filtering by route. These counts are independent of upstream truncation

onebusaway_get_schedule_for_stop _tool

• stopId required; optional date as a real YYYY-MM-DD calendar date, default (omitted or blank) today in the agency's timezone; unknown stops fail as stop_not_found
• Departures grouped by route and direction, each with scheduledDepartureTime and tripId
• serviceDateMs preserves the upstream schedule-date marker: query time for an omitted/blank date, instance-local midnight for an explicit date; it is not rounded to a service-day boundary
• Optional routeId, departureFromMs, and departureBeforeMs combine with AND; time bounds are non-negative integer Unix milliseconds, lower inclusive and upper exclusive. Selected results omit empty directions/routes; selection.total / returned count departure rows before/after selection
• Static schedule only; live predictions come from onebusaway_get_arrivals

Example: {"stopId":"1_75403","routeId":"1_100259","departureFromMs":1792882800000,"departureBeforeMs":1792886400000} selects that route's departures in the given epoch interval.

onebusaway_get_schedule_for_route _tool

• routeId required; optional date as a real YYYY-MM-DD calendar date, default (omitted or blank) today; unknown routes fail as route_not_found
• Every trip that day with tripId, tripHeadsign, serviceId, and its stop sequence
• serviceDateMs preserves the upstream route scheduleDate, identifying the schedule's service day
• Route, stop, headsign, and service metadata resolve from references first, retaining legacy metadata and grouping fallbacks where reference fields are absent or empty
• Optional exact tripId or departureFromSec / departureBeforeSec selects whole trips having any departure in the interval. Bounds are non-negative integer GTFS seconds from midnight, including values beyond 86400; lower inclusive, upper exclusive. selection.total / returned count trips before/after selection
• Static schedule only; live predictions come from onebusaway_get_arrivals at a stop

Example: {"routeId":"1_100259","departureFromSec":28800,"departureBeforeSec":32400} selects trips with any departure from 08:00 inclusive to 09:00 exclusive.

For route and block schedules, a nonblank tripId cannot be combined with departure bounds. Blank optional IDs mean omitted; either bound may be omitted, and two supplied bounds must increase. Without selectors, all three tools return their complete mapped response with no selection metadata or default cap. Selection counts describe only that upstream response, not omitted upstream service; a zero match is a successful result with a notice.

Arrivals, stop context, trips, vehicles, schedules, and alerts include a validated IANA timezone; epoch clocks and date headings carry that zone explicitly. Stop tools use the queried stop's agency namespace, vehicles the requested agency, and trip/route schedules the referenced route's agency. Each alert resolves its own agency, route, trip, and stop scopes and uses their zone only when every scope resolves and agrees. Missing, invalid, unresolved, or conflicting zones use UTC, without additional requests. Epoch numbers and GTFS seconds remain unchanged, including schedule times beyond 24:00.

onebusaway://stop/{stopId} _resource

• Stop record as application/json, the same shape onebusaway_get_stop returns
• stopId comes from onebusaway_find_stops or onebusaway_search_stops

onebusaway://route/{routeId} _resource

• Route record as application/json, the same shape onebusaway_get_route returns
• routeId comes from onebusaway_find_routes or onebusaway_search_routes

Features

Built on @cyanheads/mcp-ts-core: stdio and Streamable HTTP transports, pluggable auth (none / jwt / oauth), swappable storage (in-memory, filesystem, Supabase, Cloudflare KV/R2/D1), structured logging with optional OpenTelemetry tracing.

OneBusAway-specific:

• Wraps onebusaway-sdk with typed error classification (NotFound, RateLimited, ValidationError for an upstream 400, ServiceUnavailable)
• Defaults to the Puget Sound instance (api.pugetsound.onebusaway.org), where ONEBUSAWAY_API_KEY=TEST works for development; ONEBUSAWAY_BASE_URL points it at any other OneBusAway instance
• Stop and route IDs are agency-prefixed, {agencyId}_{localId} (stop 1_75403, route 1_100259); agency IDs are the bare prefix (1 for Metro Transit, 40 for Sound Transit)
• One shared pacer, sized by ONEBUSAWAY_RATE_LIMIT_*, queues every upstream request against the API key's budget; a call that gets no slot within the wait cap fails as retryable rate_limited with data.retryAfter, on any tool
• Transit data only, no trip planning; server-level instructions walk agents through the ID format and the common lookup chains

Agent-friendly output:

• predicted on every arrival, trip, and vehicle separates GPS-tracked data from schedule-only projections
• Machine-readable times: scheduleDeviation in seconds; arrival, stop-schedule, and update timestamps in Unix milliseconds; trip, route-schedule, and block stop times in GTFS seconds from midnight
• Chainable IDs: stopId from the stop tools feeds arrivals, tripId feeds onebusaway_get_trip, blockId feeds onebusaway_get_block, situationIds feed onebusaway_get_alert, and agencyId feeds vehicles and route listing
• Typed error contracts whose recovery hints name the next tool to call, plus a notice on empty or truncated results

Getting started

Public Hosted Instance

A public instance is available at https://onebusaway.caseyjhand.com/mcp — no installation required. Point any MCP client at it via Streamable HTTP:

{
  "mcpServers": {
    "onebusaway-mcp-server": {
      "type": "streamable-http",
      "url": "https://onebusaway.caseyjhand.com/mcp"
    }
  }
}

Self-Hosted / Local

Add the following to your MCP client configuration file. ONEBUSAWAY_API_KEY=TEST works on the Puget Sound instance without registration.

{
  "mcpServers": {
    "onebusaway-mcp-server": {
      "type": "stdio",
      "command": "bunx",
      "args": ["@cyanheads/onebusaway-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info",
        "ONEBUSAWAY_API_KEY": "TEST"
      }
    }
  }
}

Or with npx (no Bun required):

{
  "mcpServers": {
    "onebusaway-mcp-server": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@cyanheads/onebusaway-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info",
        "ONEBUSAWAY_API_KEY": "TEST"
      }
    }
  }
}

Or with Docker:

{
  "mcpServers": {
    "onebusaway-mcp-server": {
      "type": "stdio",
      "command": "docker",
      "args": [
        "run", "-i", "--rm",
        "-e", "MCP_TRANSPORT_TYPE=stdio",
        "-e", "ONEBUSAWAY_API_KEY=TEST",
        "ghcr.io/cyanheads/onebusaway-mcp-server:latest"
      ]
    }
  }
}

For Streamable HTTP, set the transport and start the server:

MCP_TRANSPORT_TYPE=http MCP_HTTP_PORT=3010 ONEBUSAWAY_API_KEY=TEST bun run start:http
# Server listens at http://localhost:3010/mcp

Prerequisites

• Bun v1.4.0 or higher (or Node.js v24+).
• A OneBusAway API key. TEST works on the Puget Sound instance for development; for production use or other instances, register at the relevant agency's developer portal.

Installation

1. Clone the repository:

git clone https://github.com/cyanheads/onebusaway-mcp-server.git

2. Navigate into the directory:

cd onebusaway-mcp-server

3. Install dependencies:

bun install

4. Configure environment:

cp .env.example .env
# edit .env — set ONEBUSAWAY_API_KEY if needed

Configuration

See .env.example for the full list of optional overrides.

Running the server

Local development

• Build and run the production version:

  shCopy

  # One-time build
  bun run rebuild
  
  # Run the built server
  bun run start:http
  # or
  bun run start:stdio
  

• Run checks and tests:

  shCopy

  bun run devcheck       # Lint, format, typecheck, security, changelog sync
  bun run test           # Vitest test suite
  bun run test:coverage  # Test suite with coverage, held to the framework thresholds
  bun run lint:mcp       # Validate MCP definitions against spec
  

Docker

docker build -t onebusaway-mcp-server .
docker run --rm -e ONEBUSAWAY_API_KEY=TEST -p 3010:3010 onebusaway-mcp-server

The Dockerfile defaults to HTTP transport, stateless session mode, and logs to /var/log/onebusaway-mcp-server. OpenTelemetry peer dependencies are installed by default — build with --build-arg OTEL_ENABLED=false to omit them.

Project structure

Development guide

See CLAUDE.md for development guidelines and architectural rules. The short version:

• Handlers throw, framework catches — no try/catch in tool logic
• Use ctx.log for request-scoped logging, ctx.state for tenant-scoped storage
• Register new tools and resources in the createApp() arrays in src/index.ts
• Wrap external API calls: validate raw → normalize to domain type → return output schema; never fabricate missing fields

Contributing

Issues are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

Apache-2.0 — see LICENSE for details.

Transit data from the default Puget Sound OneBusAway API, operated by Sound Transit and King County Metro, is governed by the Sound Transit Transit Data Terms of Use, and users of the hosted endpoint receive it under those terms. Key obligations:

• Clause 2: usage metrics are available on request.
• Clause 3: data is fetched live from the OneBusAway API and is not modified or cached beyond the request cycle.
• Clause 4: you agree to pass substantially similar terms through to any users you provide this data to.
• Clause 7: this server does not use Sound Transit trademarks in its name or branding.