Tfl MCP Server

TfL MCP Server

Disclaimer: This is a community-built project. It is not affiliated with, endorsed by, or connected to Transport for London (TfL). This project consumes the publicly available TfL Unified API.

An MCP server that exposes the TfL (Transport for London) Unified API as tools, allowing AI assistants like Claude to query live London transport data.

Version 2 is a single Node.js 22 implementation using the MCP 2026-07-28 protocol revision. It supports stdio for local hosts, npm, and MCPB, plus stateless Streamable HTTP at /mcp for remote deployments.

Protocol compatibility: Streamable HTTP is modern-only MCP 2026-07-28. The stdio entry point also accepts 2025-era initialization for desktop hosts such as Codex, while modern stdio clients continue to negotiate 2026-07-28. Legacy HTTP/SSE is not supported.

Getting Started

Step 1 — Add to Claude Desktop

Open your Claude Desktop config file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

Option A: Node.js MCPB (recommended)

Download tfl-mcp-server.mcpb from GitHub Releases and install it in Claude Desktop.

Option B: npm

With Node.js 22 or later installed, point Claude Desktop at the published package:

{
  "mcpServers": {
    "tfl-mcp-server": {
      "command": "npx",
      "args": ["-y", "@oneill9/tfl-mcp-server@2.0.0"],
      "env": { "TFL_APP_KEY": "your_key_here" }
    }
  }
}

Option C: Docker

{
  "mcpServers": {
    "tfl-mcp-server": {
      "command": "docker",
      "args": ["run", "-i", "--rm", "-e", "TFL_APP_KEY", "ghcr.io/oneill9/tfl-mcp-server:latest"]
    }
  }
}

Step 2 — Add a TfL API key (recommended)

Without a key, TfL applies strict rate limits that will impact most real-world usage. Register a free key and pass it via the TFL_APP_KEY environment variable. The Docker example's -e TFL_APP_KEY forwards this value into the container:

"env": { "TFL_APP_KEY": "your_key_here" }

Step 3 — Restart Claude Desktop and start asking questions

Example: "Is the Central line running normally?", "When is the next bus from Oxford Circus?"

For source, Docker, and Streamable HTTP options, see docs/installation.md.

Tools

Note: The server uses the /StopPoint/Search/{query} endpoint internally to automatically resolve stop names to NaPTAN IDs for the arrivals, crowding, and fares tools.

MCP Apps UI

The service_status tool includes MCP Apps support as a progressive enhancement. UI-capable hosts (e.g. Claude Desktop) can render an interactive service status board alongside the text response. Non-UI hosts continue to receive the standard text output.

• The UI is self-contained (inline HTML/CSS, no external assets)
• Structured JSON data is returned alongside the text fallback
• No additional setup is required — host support is detected automatically

See docs/tools.md for full details.

Authentication

The MCPB and default container mode use stdio transport. The optional Streamable HTTP mode does not implement OAuth or any other server-side authentication; deploy it only behind an appropriate trusted access layer.

The TfL API uses a simple API key (TFL_APP_KEY) that you supply as an environment variable. A key is strongly recommended — without one, TfL applies strict rate limits that will impact most real-world usage. Registration is free. No OAuth flow, login, or account beyond the TfL portal is required to use this MCP server.

Configuration

An API key is strongly recommended — without one, TfL's strict rate limits will impact most real-world usage. Registration is free at api-portal.tfl.gov.uk.

Running from source

Node.js 22 or later is required. Install from the lockfile and build before starting the server.

cd node
npm ci
npm run build
node dist/index.js

That starts stdio transport. For stateless Streamable HTTP:

cd node
HOST=127.0.0.1 PORT=8080 node dist/index.js --http

Connect an MCP 2026-07-28 client to http://127.0.0.1:8080/mcp. Set MCP_ALLOWED_HOSTS to a comma-separated hostname allowlist when serving under other hostnames.

For use with Claude Desktop, see docs/installation.md.

Testing

Unit tests use a mock HTTP server — no network access or API key required:

cd node && npm test

The Streamable HTTP acceptance tests are included in npm test. Run the official frozen MCP 2026-07-28 requirement set separately (optional extension probes outside that set are not scored):

cd node && npm run test:conformance

The conformance fixture registers the real production TfL tools and resource through the shared modern-only HTTP adapter. It also adds test-only diagnostic tools, resources, prompts, and flows needed by the referee's hard-coded probes; those diagnostics are not exposed by the production entry point.

Contract tests call the live TfL API:

cd node && TFL_APP_KEY=your_key_here npm run contractTest

Build and smoke-test the packed npm CLI, MCPB, and container distributions with bash scripts/test-distributions.sh. The script skips container checks when Docker is unavailable.

Support

For questions, bug reports, or feature requests, please open an issue on GitHub Issues.

Privacy Policy

This MCP server acts as a local proxy between your AI assistant and the TfL Unified API. It does not collect, store, or transmit any personal data beyond what is required to forward your queries to TfL.

• Data collection: No analytics or telemetry is collected. Limited operational diagnostics are written to standard error but are not persisted by the server; a host may retain them under its own logging policy.
• Usage and storage: Queries are forwarded to TfL in real time and responses are returned immediately. No query history or results are persisted.
• Third-party sharing: Requests are forwarded to the TfL Unified API (api.tfl.gov.uk). See TfL's privacy policy for how TfL handles API usage data.
• Data retention: The server retains no data and holds no state between requests. Host-managed standard-error retention is outside the server's control.
• Contact: For privacy concerns, open an issue at https://github.com/oneill9/tfl-mcp-server/issues.

The full privacy policy is available at PRIVACY.md.

Compliance

This server has been reviewed for compliance with the Anthropic Software Directory Terms and Anthropic Software Directory Policy. See COMPLIANCE.md for the full compliance statement and maintainer commitments.

TfL API Reference

• Unified API: https://api.tfl.gov.uk/
• API Portal / Key Registration: https://api-portal.tfl.gov.uk/
• Swagger UI: https://api.tfl.gov.uk/swagger/ui/index.html