Arlet

Connect Japan Transit Data (ODPT) to Codex

Query Japan Transit Data (ODPT) directly from Codex. Arlet links the two through one MCP connection and takes care of API keys.

This server connects your AI client to the Open Data Center for Public Transportation (ODPT), operated by the Association for Open Data of Public Transportation in Japan.

Two kinds of data are covered:

1. GTFS feeds (101 of them) that ODPT distributes for bus, rail and ferry operators. This is the important complement to the GTFS data repository (gtfs-data.jp), which is mostly community buses outside the big cities: through ODPT you also get Kyoto city bus and subway, Tokyo Metro, Toei subway, Tsukuba Express, Tokyo Rinkai, Iyotetsu bus, Sendai municipal bus and around twenty ferry operators. Search feeds by name or mode, find stops, then get departures for a specific date resolved against the feed's service calendar. 2. Realtime and reference APIs: rail station search, station departure timetables by direction and day type, live train service information (delays, suspensions), operator lists, and airport departure/arrival flight information.

Notes: a free developer registration at developer.odpt.org issues the access token (consumer key), which stays in your own Arlet environment variables. Data licences are set per provider (most are the Public Transportation Open Data Basic Licence or CC BY 4.0), and every response includes the attribution and a reminder to check the provider's licence. What your key can access follows the permissions ODPT grants to your account.

How to connect Japan Transit Data (ODPT) to Codex

  1. 1

    In the Arlet dashboard, open Data tools, find Japan Transit Data (ODPT), set the API key issued by Japan Transit Data (ODPT) and switch it on.

  2. 2

    In your terminal, run codex mcp add arlet --url https://mcp.arlet.dev/mcp/ to add Arlet as an MCP server.

  3. 3

    Codex detects OAuth support and opens your browser. Sign in with Google and click Allow on the consent screen.

  4. 4

    Once connected, both the CLI and the IDE extension can call Arlet tools (the configuration is shared).

If the browser does not open, run codex mcp login arlet to redo the authentication.

Use Japan Transit Data (ODPT) with other AI clients