Trimet MCP Server

@pipeworx/trimet

Live arrivals, stop lookup, vehicle positions and service alerts for Portland, Oregon — TriMet bus, MAX light rail, WES commuter rail and Portland Streetcar.

Part of Pipeworx — an MCP gateway connecting AI agents to 1684+ live data sources.

Requires an API key (TriMet calls it an appID) — free and self-service at https://developer.trimet.org/appid/registration/.

• Platform key: PLATFORM_TRIMET_KEY
• Caller-supplied: _apiKey argument on any tool

Tools

Traps

Two APIs on one credential, and they disagree about case. The modern JSON web service is /ws/v2/... (lowercase v). The GTFS-Realtime feeds are /ws/V1/... (uppercase V) and answer protobuf, not JSON. Getting the case wrong returns an error page, not a redirect.

TriMet reports failures inside a 200 body. An invalid stop id or a bad parameter comes back as HTTP 200 with resultSet.errorMessage set and an empty arrival list. readJson() checks for it and throws, so the caller sees the real reason instead of "no buses are coming".

Quick Start

Add to your MCP client (Claude Desktop, Cursor, Windsurf, etc.):

{
  "mcpServers": {
    "trimet": {
      "url": "https://gateway.pipeworx.io/trimet/mcp"
    }
  }
}

What this endpoint actually serves

tools/list at https://gateway.pipeworx.io/trimet/mcp returns the tools in the table above plus the shared Pipeworx meta-tools — ask_pipeworx, discover_tools, search_within, remember/recall and the rest of the gateway-wide set. So the tool count you see is larger than this table: a single-pack endpoint currently lists roughly 30 shared tools alongside the pack's own. The connection's initialize response states its exact scope, and is the authoritative answer for a given day.

This is deliberate, not multiplexing by accident. The meta-tools are what let a scoped connection answer a question this pack does not cover — via ask_pipeworx, which routes across the whole catalog — without you adding a second MCP server. There is currently no way to mount a pack endpoint without them; if the extra schemas cost you more context than the routing is worth, connect to the full gateway once rather than to several pack endpoints.

Or connect to the full Pipeworx gateway to get every pack's tools listed directly, instead of just this one's:

{
  "mcpServers": {
    "pipeworx": {
      "url": "https://gateway.pipeworx.io/mcp"
    }
  }
}

Both URLs reach the same gateway and the same 1684+ data sources. The only difference is which pack's tools are listed directly; ask_pipeworx reaches all of them from either one.

No MCP client? Call it over HTTP

curl -X POST https://gateway.pipeworx.io/v1/tools/trimet_arrivals \
  -H 'Content-Type: application/json' \
  -d '{"stop_ids":"7646"}'

No account needed for the first calls. Inspect any tool: GET https://gateway.pipeworx.io/v1/tools/trimet_arrivals. Find one: POST https://gateway.pipeworx.io/v1/tools/search_packs with {"query":"..."}.

Standalone (no gateway account)

This package also runs as a local stdio MCP server — no Pipeworx account, no gateway round-trip:

{
  "mcpServers": {
    "trimet": {
      "command": "npx",
      "args": ["-y", "@pipeworx/mcp-trimet"]
    }
  }
}

Or run it directly to confirm it starts:

npx -y @pipeworx/mcp-trimet

It speaks MCP over stdin/stdout and answers initialize/tools/list/tools/call for only this pack's tools — none of the shared meta-tools the gateway connection above adds. Same source, same tools, no ask_pipeworx routing.

Using with ask_pipeworx

Instead of calling tools directly, you can ask questions in plain English — this works on the pack endpoint above as well as on the full gateway:

ask_pipeworx({ question: "your question about Trimet data" })

The gateway picks the right tool and fills the arguments automatically.

More

• Docs and guides
• pipeworx.io

License

MIT