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Tools

15 tools covering the full OneBusAway transit data surface — discovery, real-time operations, schedules, alerts, and block schedules:

onebusaway_find_stops

Find bus stops near a geographic location.

• Configurable search radius (default 300m, max ~1600m before results degrade)
• Optional stop code filter (the number printed on the sign, e.g. 75403)
• Returns stop ID, code, name, direction, served route IDs, and wheelchair boarding status
• limitExceeded flag signals when more stops exist beyond the returned set
• Stop IDs returned here feed directly into onebusaway_get_arrivals

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onebusaway_get_arrivals

Real-time arrivals and departures at a stop.

• Configurable time window (minutesBefore, minutesAfter — defaults 5/35)
• predicted boolean distinguishes GPS-tracked estimates from schedule-only projections
• Schedule deviation in seconds (positive = late, negative = early)
• Vehicle position and stops-away count when available
• Active service alert summaries included inline
• tripId on each arrival feeds onebusaway_get_trip for vehicle tracking

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onebusaway_get_trip

Real-time status and stop sequence for a specific trip.

• Journey phase (in_progress, layover_before, layover_during)
• Vehicle GPS position, heading, and schedule deviation
• Full stop sequence with GTFS arrival/departure times and distance along trip
• Optional serviceDateMs for looking up trips from a prior service day

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onebusaway_get_vehicles

Real-time positions of all active vehicles for an agency.

• Returns GPS coordinates, heading, schedule deviation, and current trip for every active vehicle
• Optional routeId filter (applied client-side after fetching all agency vehicles)
• Phase and predicted flag distinguish actively-reporting vehicles from stale entries

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onebusaway_search_routes

Search for routes by name or number across the instance.

• Falls back gracefully: the Puget Sound instance returns 404 on the search endpoint — onebusaway_find_routes (lat/lon) or onebusaway_list_routes_for_agency are the alternatives
• Error contract surfaces this with structured recovery hints

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onebusaway_get_schedule_for_stop and onebusaway_get_schedule_for_route

Static schedule lookups — full-day timetables without real-time data.

• Date parameter (ISO 8601) defaults to today in the agency's timezone
• onebusaway_get_schedule_for_stop: all departures grouped by route and direction, with trip IDs for follow-up calls
• onebusaway_get_schedule_for_route: all trips for the route with full stop sequences and GTFS stop times

Resources

All resource data is also reachable via onebusaway_get_stop and onebusaway_get_route. Stop and route IDs use agency-prefixed format: {agencyId}_{localId} (e.g. 1_75403, 1_100259).

Features

Built on @cyanheads/mcp-ts-core:

• Declarative tool and resource definitions — single file per primitive, framework handles registration and validation
• Unified error handling — handlers throw, framework catches, classifies, and formats
• Pluggable auth: none, jwt, oauth
• Swappable storage backends: in-memory, filesystem, Supabase, Cloudflare KV/R2/D1
• Structured logging with optional OpenTelemetry tracing
• STDIO and Streamable HTTP transports

OneBusAway-specific:

• Wraps onebusaway-sdk with typed error classification (NotFound, RateLimited, ServiceUnavailable)
• Defaults to the Puget Sound instance (api.pugetsound.onebusaway.org) — works with ONEBUSAWAY_API_KEY=TEST for development
• Configurable ONEBUSAWAY_BASE_URL for any OneBusAway-compatible instance (NYC, Washington DC, Tampa, etc.)
• Server-level instructions guide agents through stop ID format, recommended workflows, and OneBusAway's limitations (no trip planning)

Agent-friendly output:

• predicted boolean on every arrival and vehicle distinguishes GPS-tracked data from schedule-only projections — agents branch on data, not string parsing
• Schedule deviation in seconds on arrivals, trips, and vehicle positions — structured for countdown timer math
• Cross-tool linkage: tripId from arrivals feeds onebusaway_get_trip; stopId from searches feeds arrivals; agencyId from list feeds vehicles and route listing
• Structured error contracts with recovery hints (onebusaway_search_routes 404 → fallback to onebusaway_find_routes or onebusaway_list_routes_for_agency)

Getting started

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 v1.3.0 or higher (or Node.js v24+).
• An 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

All configuration is validated at startup via Zod schemas. Key environment variables:

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

Running the server

Local development

• Build and run the production version:

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

• Run checks and tests:

  bun run devcheck   # Lint, format, typecheck, security, changelog sync
  bun run test       # Vitest test suite
  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 and pull requests are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

Data

Transit data is sourced from the Puget Sound OneBusAway API, operated by Sound Transit and King County Metro. Use of this data is governed by the Sound Transit Transit Data Terms of Use.

Downstream users of this server's hosted endpoint receive data subject to those terms. Key obligations include:

• 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 through substantially similar terms to any users you provide this data to.
• Clause 7 — This server does not use Sound Transit trademarks in its name or branding.

License

Apache-2.0 — see LICENSE for details.