traintracker
Traintrackr is an MCP server that answers questions about GB National Rail trains — live boards, timetables, platforms, service details and journey plans.
Find stations by name, partial name or 3-letter CRS code, best match first.
Live departure boards for the next ~2 hours: expected times, platforms, delays, cancellations, optional calling points, filter by destination, shift the start time.
Live arrivals for the next ~2 hours, optionally only trains that called at a given station earlier.
Which platform a specific train leaves from (live, or booked and flagged as such until announced).
Next trains from one platform in the next ~2 hours.
Booked timetables for any date the timetable covers, departures or arrivals, with time window and origin/destination filters.
Service details: every stop for one train, with live times where available.
Plan journeys A to B with up to 6 changes, including approximate cross-London walk/Tube links, live Darwin overlay and at-risk connection flags.
Report data status: which sources are configured and how fresh the timetable is.
Provides tools for querying GB National Rail train information, including live departures and arrivals, departure platforms, timetables, service details, and journey planning with connections and live status overlays.
Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@traintrackerwhen's the next train to Sudbury?"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
Traintrackr
An MCP server that lets Claude and ChatGPT answer questions about GB (National Rail) trains: "when's the next train to Sudbury?", "is the 13:00 from Liverpool Street on time?", "how do I get from Cambridge to Sudbury next Saturday morning?"
The public service runs at traintrackr.live. It is free, and you sign in with an email address; there is no password. The connector address is:
https://traintrackr.live/mcpUse it
Claude. Traintrackr is listed in Claude's connector directory: open claude.ai/directory/traintrackr, or in claude.ai open Customize → Connectors, choose the + next to Connectors and find Traintrackr in the directory. Choose Connect: Claude opens the Traintrackr sign-in page, where you enter your email address and then open the link, or type the six-digit code, in the email it sends. A connector added in claude.ai also works in Claude Desktop and the mobile apps. To add it by address instead, choose Add custom connector, name it Traintrackr and paste the connector address.
ChatGPT. ChatGPT adds it through developer mode, on the web, in Plus, Pro, Business, Enterprise and Edu plans; in a workspace, an admin may have to allow developer mode first. Turn on Settings → Security and login → Developer mode, then at chatgpt.com/plugins choose +, name it Traintrackr, paste the connector address and choose OAuth. Sign in with your email address as above. In a new chat, choose + → Developer mode and select Traintrackr.
Then ask about trains. traintrackr.live/docs shows what each answer contains, and the limits. The privacy policy and terms of use are on the site too. The server is listed in the MCP Registry as live.traintrackr/traintracker.
The rest of this README describes how the server works and how to run your own copy: locally over stdio for the Claude desktop app, or hosted over HTTP (see Deploy to Render). The timetable is stored in Postgres.
flowchart LR
Claude[Claude] <-->|stdio or HTTP| TT[traintracker]
subgraph Live["Live, next ~2 hours"]
D[Darwin<br/>Rail Data Marketplace]
end
subgraph Timetable["Timetable, any future date"]
NR[Network Rail<br/>SCHEDULE feed] -->|daily download| DB[(Postgres<br/>timetable schema)]
end
TT --> D
TT --> DBRelated MCP server: railinfo-mcp
Tools
Tool | Answers | Data |
| "Which Sudbury?" Station names ↔ CRS codes | Bundled station list |
| Next trains, expected times, platforms, delays, cancellations | Darwin; if it's not set up, booked times; if it's offline, booked times with a note saying so |
| "Which platform is the 13:00 to Colchester?" One train's platform, flagged | Darwin (paged); booked platform from the timetable until the live one is announced |
| "What are the next three trains from platform 7?" | Same as |
| Trains arriving in the next ~2 hours | Darwin arrivals; if not set up, booked times; if offline, booked times with a note saying so |
| "Show me the departures board for Liverpool Street." The same live departures or arrivals, drawn as a departure board | Same as |
| Booked departures/arrivals at a station on any date | Local timetable |
| Every stop for one train | Whichever source issued the ID |
| A to B with changes (up to | Local timetable + Darwin live overlay |
| What's configured, timetable freshness, what's missing; with | — |
| "What do you keep about me?" The privacy policy as text, with the page's address | The |
Every tool accepts station names or CRS codes. Ambiguous names ("Sudbury", "Harrow") return the candidates so Claude can ask which one you meant.
Departure board
show_board comes with an MCP App: a client that supports MCP Apps draws its result as a split-flap departure board next to the answer. A client draws the board for every call of a tool that has one, so it is on a tool of its own, which the assistant is told to use only when someone asks to see a board. live_departures and live_arrivals return the same trains and draw nothing. A client without MCP Apps gets show_board's result as it would theirs.
The board is one page, apps/rail/ui/board.html, served as the resource ui://traintracker/board.html. Its style and script are inline and it loads nothing from anywhere. The client hands it the tool's result; it shows up to 12 trains, the station's notices and the data credit. Refresh asks the client to call show_board again with the same arguments, which counts against the rate limit like any other call. The flaps don't turn for someone who has asked their system for reduced motion, and a screen reader gets the trains as a table.
Run your own copy
Everything from here on is for running the server yourself. The public service at traintrackr.live is this code, deployed as described in Deploy to Render.
Try it without accounts (demo mode)
Set TRAINTRACKER_DEMO=1 to test every tool before your accounts are approved. The server then uses generated example data and makes no network requests:
Timetable: a generated SCHEDULE feed for 25 real stations in East Anglia and London (Liverpool Street, Stratford, Chelmsford, Colchester, Ipswich, Norwich, Marks Tey, Sudbury, Cambridge, Kings Cross and others), running from today for 90 days. Sundays start later. It is stored in its own schema (
timetable_demo), apart from the real timetable, and rebuilt each day. Demo mode still needsDATABASE_URL.Live boards: Darwin departure, arrival and service-details responses are generated from that timetable in-process. About one train in five runs late, one in 25 is cancelled and one in 12 has a platform change; the same train on the same day always gets the same result. Large stations (Liverpool Street, Kings Cross, Cambridge, …) announce platforms 15 minutes before departure, so the booked-platform fallback gets exercised.
Every board and plan carries a note that the data is generated, and data_status reports demo_mode. Ask for stations outside the demo network and you get an empty board.
"env": { "TRAINTRACKER_DEMO": "1" }Add that to the traintracker entry in the Claude desktop config (see Add to the Claude desktop app), or put TRAINTRACKER_DEMO=1 in .env. Remove it once your keys are in place. Things to try: "next trains from Liverpool Street", "which platform is the next train from Cambridge to Kings Cross?", "how do I get from Cambridge to Sudbury tomorrow at 9?"
Accounts you need
# | Account | Needed? | Cost | What it provides | Used for |
1 | Rail Data Marketplace — Live Departure Board product | Yes for live times | Free | Darwin: National Rail's real-time feed. Departure boards for the next 2 hours with expected times, platforms, delay/cancellation reasons, calling points, station alerts. The same data as station screens. |
|
2 | Network Rail Open Data (NTROD) — SCHEDULE feed | Yes for timetables and planning | Free | The full GB passenger timetable from Network Rail's planning system, including short-term changes (engineering works, extra trains, cancellations) once published. Refreshed daily. |
|
3 | Rail Data Marketplace — Service Details product | Optional | Free | Full live calling pattern for a train seen on a Darwin board. |
|
4 | Rail Data Marketplace — Live Arrival Board product | Optional | Free | Darwin arrivals boards. Without it, arrivals show booked times. |
|
1. Rail Data Marketplace (Darwin)
Create an account at raildata.org.uk.
In the product catalogue, search "Live Departure Board" (the LDBWS product, not "Live Fastest Departure Boards") and subscribe. Approval for the free tier ranges from instant to a few days.
Open the subscribed product → Specification tab. Copy the Consumer key (not the secret) into
DARWIN_API_KEY.Check the base URL on that tab matches
DARWIN_DEPARTURES_URLin.env.example. If it differs, setDARWIN_DEPARTURES_URLto your value (everything before/GetDepBoardWithDetails).(Optional) Subscribe to Service Details and Live Arrival Board the same way. Each product has its own key and URL: set
DARWIN_SERVICE_API_KEY/DARWIN_SERVICE_URLandDARWIN_ARRIVALS_API_KEY/DARWIN_ARRIVALS_URL.
2. Network Rail Open Data (SCHEDULE)
Register at the Network Rail data feeds portal. Activation can take a while.
Sign in and check that SCHEDULE appears under Static feeds.
Put your portal username and password in
NR_USERNAMEandNR_PASSWORD.If the portal gives a different download link for the full daily extract, all operators, JSON than
NR_SCHEDULE_URLin.env.example, setNR_SCHEDULE_URLto it.
The server downloads the feed in the background when the timetable is missing or older than 26 hours. It checks this on start-up and on every tool call, so a server left running for days stays current. If a download fails it keeps serving the old timetable, and data_status shows the error. You can also run manage.py refresh_timetable --commit by hand (see Commands). Set TIMETABLE_AUTO_REFRESH=0 where a separate job runs refresh_timetable, as on Render.
3. Postgres
The timetable lives in one schema (timetable by default) of the database in DATABASE_URL. The role needs to create schemas in that database; the owner of the database can. On a shared server, give traintracker its own database and role:
CREATE ROLE traintracker LOGIN PASSWORD '…';
CREATE DATABASE traintracker OWNER traintracker;
REVOKE CONNECT ON DATABASE traintracker FROM PUBLIC;Put that role in DATABASE_URL, not the server's own user. The server's user owns every database on it, so a fault in traintracker would reach the other applications' data; the traintracker role reaches its own database only.
The full GB timetable takes about 475 MB (4.3 million stops), and about twice that while a refresh builds the new copy. A refresh takes about 40 seconds plus the download. It builds the new timetable in a staging schema and swaps it in with a rename, so readers never see a half-built timetable, and an advisory lock stops two refreshes running at once.
The tables are UNLOGGED: they are rebuilt from the feed every day, so they skip the write-ahead log and don't add to the server's WAL or point-in-time-recovery storage. The cost is that Postgres empties them after a crash; the tools then report "No timetable yet" until the next refresh.
How each source is used
flowchart TD
Q{What's being asked?}
Q -->|next ~2 hours| L[live_departures / live_arrivals]
Q -->|a future date| T[timetable]
Q -->|A to B| P[plan_journey]
Q -->|one train| S[service_details]
L --> L1{Darwin key?}
L1 -->|yes| Darwin
Darwin -->|error or timeout:<br/>note says Darwin is offline| TT
L1 -->|no| TT[(Timetable<br/>booked times, flagged)]
T --> TT
P --> CSA[Connection Scan<br/>over the day's timetable]
CSA --> OV{Today, departing<br/>within 2 hours?}
OV -->|yes| Darwin2[Darwin expected times<br/>+ tight-connection flag]
Darwin2 -.->|offline| Note[Plan note: Darwin offline,<br/>times are booked]
S --> ID{ID prefix}
ID -->|darwin:| Darwin3[Darwin Service Details]
ID -->|tt:| TTSource | Freshness | Coverage | Cached for | Limits to know |
Darwin | Real time | Now → +2 hours | 20 s | Darwin service IDs expire soon after the train runs |
Timetable (Postgres) | Daily (Network Rail publishes ~06:00) | Two days back → end of the published timetable (usually months) | Until the next rebuild | Booked times only; last-minute changes show up in Darwin, not here |
Trainline links
A train from the timetable (timetable, plan_journey, service_details with a tt: ID, and the live tools when they fall back to booked times) carries trainline_url: that train's page on Trainline, with its stops and how it is running. The address is <TRAINLINE_LIVE_URL>/departures/<station>/<token>, where the token is the base64 of /callingPattern/<train UID>/<run date>. The station only titles the page: the board's station, the station a leg is boarded at, or the train's origin.
Trains from Darwin have no link: a Darwin service ID carries no train UID.
Trainline names stations by a slug of its own name for them. Most follow from the name in the station list;
trainline_slugs.jsonholds the ones that differ, andnullfor stations Trainline has no live board for (mostly ones opened since 2022). A train that calls only at those has no link.Trainline publishes no specification for these addresses. They were read off its live boards, and the slugs checked against its sitemap of live pages, in September 2026. For a train it doesn't know, Trainline shows the station's board.
Demo mode gives no links: its trains are made up.
Darwin allowance
Free Darwin access covers 5 million requests per four-week railway period, and one server key serves every user. The server counts the requests it sends to Darwin and reports the total in manage.py rail_status, and in data_status when DJANGO_DEBUG=1 (a hosted server doesn't tell everyone who signs in how much is left):
Darwin usage: 412,906 requests in the last 28 days, 8.26% of 5,000,000What is counted: each request sent to Darwin, failed ones included. A board answered from the 20-second cache sends nothing and counts nothing. Demo mode counts nothing.
The period: a rolling 28 days. Railway periods are not simple to derive (the first and last of the year vary in length), and a rolling window is never less strict than the period it overlaps.
Per product: the count is kept for each Rail Data Marketplace product (
departures,arrivals,service) and the percentage uses the total. If your allowance is per product, the percentage overstates your usage.Daily limit: the server sends Darwin at most
DARWIN_DAILY_LIMITrequests in one UK day (170,000 by default; the allowance works out at about 178,000 a day). Past that the live tools answer with booked times, and say why, until midnight. The count for the day is resumed after a restart.0turns the limit off.Warnings: the log gets a warning when usage passes 70% of the allowance and another at 90%. Each is given once, and again only if usage falls below the mark and returns, or the server restarts above it.
Storage: one small table,
darwin_requests, in its own schema (USAGE_SCHEMA), so the count survives restarts and timetable refreshes. Counts gather in memory and are written when 50 are waiting or a minute has passed, and at shutdown; a server that is killed loses at most that many. A failed write is logged and retried, and never fails a tool call. Rows older than 60 days are deleted.
What the timetable keeps
The SCHEDULE feed is large (all trains, freight included). On import, traintracker keeps only what a passenger needs:
Passenger categories only (trains, replacement/timetabled buses, ships). Freight and empty stock are dropped, except overlay and cancellation records, which can stop a passenger train running on a given day.
Stops with a public time only; junctions and passing points are dropped.
Schedules that ended more than two days ago are dropped.
The timetable therefore covers two days before it was built up to the last date any schedule runs, and a tool asked about a date outside that says so.
For each date it applies Network Rail's precedence rules per train: cancellation (C) beats new (N), which beats overlay (O), which beats permanent (P), and it honours each schedule's running days and date range. Bank-holiday running flags are not applied yet, so on bank holidays check the live board.
Journey planning
plan_journey uses a round-based Connection Scan over every train hop of the day: round n finds the earliest arrival using at most n trains. That gives the fastest journey and the slower options with fewer changes in one pass, up to max_changes. It repeats from just after each departure to find the next few options, then drops any option that another beats on departure, arrival and changes at once, so you're never told to leave earlier than necessary. Results are ordered by arrival, and the fewest-changes option is always included.
Minimum change time: 5 minutes between trains by default (
MIN_INTERCHANGE_MINUTES). Walk/Tube links already include time to get in and out of stations, so no extra change time is added after them.Cross-London: the Tube isn't in the rail timetable, so transfers between London terminals (Kings Cross, Liverpool Street, Waterloo, etc.) are approximated: walks under 0.8 km at walking pace plus 5 minutes, otherwise Tube at ~12 minutes plus 3.5 minutes per km. They're labelled
tube (approx.).Live overlay: for today's legs departing within two hours, Darwin's expected times and platforms are added, and
connection_at_riskis set if a delay or cancellation eats into a change, including one made via a walk/Tube link. If Darwin is down, the plan is still returned without live times.The search covers the service day (trains running into the early hours are included); it doesn't carry over to the next morning. Station boards do include trains just after midnight.
Load: a plan scans the day's trains several times, and the network for a date takes seconds to build and over a hundred megabytes to hold. Two dates are kept in memory. Timetable reads and plans run in threads, two at a time; a call that waits more than 10 seconds for its turn is told the server is busy.
Install
Requires uv, Python 3.14 (uv installs it from .python-version) and a Postgres database (any version from 13). Locally, Docker (or OrbStack) is the quickest way to get one:
docker run -d --name traintracker-pg --restart unless-stopped \
-e POSTGRES_PASSWORD=postgres -p 127.0.0.1:55432:5432 postgres:17git clone git@github.com:hugorodgerbrown/traintracker.git
cd traintracker
uv sync
cp .env.example .env # fill in your keys and DATABASE_URL (.env is git-ignored)
uv run python manage.py migrate
uv run python manage.py refresh_timetable --commit # first timetable download (a few minutes)
uv run python manage.py rail_status
uv run python manage.py runserver # the site, sign-in and /mcp at localhost:8000Add to the Claude desktop app
Edit ~/Library/Application Support/Claude/claude_desktop_config.json. Use the full path to uv (run which uv), because the app doesn't use your shell's PATH:
{
"mcpServers": {
"traintracker": {
"command": "/Users/hugo/.local/bin/uv",
"args": ["run", "--directory", "/Users/hugo/Projects/traintracker", "python", "manage.py", "serve_stdio"]
}
}
}--directory makes the project folder the working directory, so the server reads your keys from .env there. serve_stdio answers only the app that started it, so it has no sign-in and no rate limit. Keys can go in an "env" block in this file instead; real environment variables take precedence over .env.
Restart the Claude app, then ask "what's the status of traintracker's data sources?" to check everything is connected.
Configuration
All configuration is by environment variable, read from .env in the project folder if present. See .env.example. Local development needs none of the Django settings; on Render, titan's env groups set them (see Deploy to Render).
The Django settings, in config/settings.py:
Variable | Default | Purpose |
|
|
|
| a development key | Required with |
| a fixed development key | Required with |
|
| Comma-separated host names the site answers; Render's |
| — | Comma-separated origins trusted for form posts |
|
| The public address: links in emails, the passkey origin, and the connector address the site shows ( |
|
| Proxies in front of the app; the client address for the limits is that many hops from the end of |
|
| SMTP relay for the sign-in email. For Resend: host |
| — | SMTP login. For Resend: user |
|
| STARTTLS to the relay |
|
| Sender of the sign-in email; its domain must be verified with the relay |
| host name of | Where passkeys work (see docs/accounts.md) |
| — | Turns on cookieless visitor counts by fivebar for that domain; off when empty |
| — | With |
The train tools' settings, read by apps/rail/config.py:
Variable | Default | Purpose |
| — | Live Departure Board consumer key |
| RDM LDBWS URL | Override if your Specification tab differs |
| board key / RDM URL | Service Details product |
| — | Live Arrival Board product |
| — | Network Rail data feeds login |
| full daily JSON extract | Override if the portal gives a different link |
| — | Postgres database for the timetable (required), and for Django's own tables |
|
| Schema the timetable lives in (demo mode appends |
|
| Schema for the count of requests sent to Darwin (see Darwin allowance) |
|
| Most requests sent to Darwin in one UK day; past it the live tools answer with booked times. |
|
|
|
|
| Re-download when older than this |
|
| Where the feed is downloaded to before import |
|
| Tool calls per account per minute on |
|
| Tool calls an account can make at once before the per-minute rate applies |
| — | Token from OpenAI's plugin portal. When set, it is returned at |
|
| Minimum change time for planning |
|
| Base of the Trainline link on timetable services |
|
| Upstream request timeout |
| off |
|
| off |
|
Commands
Every command is a Django management command, run as uv run python manage.py <command>. The ones that change data only say what they would do unless given --commit.
Command | Does |
| Run the site, sign-in and |
| Run the MCP server on stdio (what the Claude desktop app and the MCP Inspector run). No sign-in and no rate limit |
| Create or update Django's tables |
| Download the SCHEDULE feed and rebuild the timetable (in demo mode, rebuild the generated timetable) |
| Build the timetable from a feed file you downloaded yourself (JSON, gzipped or not) |
| Show configured sources, Darwin allowance used and timetable details |
| Delete the account for an email address, with its passkeys, its connected apps' tokens and any sign-in request (an erasure request) |
| Close the account for an address, or make a closed one, so it can't sign in and its connected apps stop |
| Delete accounts with no sign-in and no new token for 180 days |
| Delete sign-in requests past their expiry |
| Delete idempotency records past their 24-hour window (Titan's) |
| Delete expired OAuth tokens (django-oauth-toolkit's) |
The account commands are described in docs/accounts.md. Under serve_stdio, logs go to stderr and stdout carries the MCP protocol.
Deploy to Render
render.yaml defines three services in Frankfurt:
Service | Type | Does | Environment |
| Web service, 512 MB, traintrackr.live | gunicorn, one worker with 8 threads. The build runs | Env groups |
| Cron job, 06:30 UTC daily |
| Env groups |
| Cron job, 03:17 UTC daily |
| Env groups |
The two env groups are made by titan, the command-line tool that comes with django-titan-template. titan is shared by every Titan app (debug off, the Python version, hosts and origins, the SMTP relay); traintracker is this app's own (DATABASE_URL, DJANGO_SECRET_KEY, ACCOUNTS_EMAIL_KEY, the mail key and sender, SITE_URL, FIVEBAR_DOMAIN and, added by hand, FIVEBAR_TOKEN). ACCOUNTS_EMAIL_KEY makes the one-way hash each account is found by: keep a copy, and never change it (docs/accounts.md). The Blueprint refers to them without declaring them, so a sync never overwrites them; a value set on a service wins over its groups'. The web service runs one worker because the train tools share one event loop, one Darwin budget and one journey network per process (the decision). It holds one day's journey network in memory for plan_journey (about 200 MB), so it needs at least 512 MB.
Run
titan deploy traintracker. It makes what the Blueprint needs before the first deploy: the sharedtitangroup, the app's role and database on the shared Postgres instance, a sending-only Resend key, and thetraintrackergroup. Then it deploys the Blueprint, adds the domaintraintracker.<parent domain>to the service, and checks/healthzon itsonrender.comname. SetDARWIN_API_KEY,OPENAI_APPS_CHALLENGE,NR_USERNAMEandNR_PASSWORDon their services when Render asks for them.Run the
traintracker-refreshcron job once by hand (Trigger Run) to load the first timetable.Put the service on its domain. titan's own
golivepoints an app at<slug>.<parent domain>; this deployment keepstraintrackr.live, which the directory listings, the MCP Registry and people's connectors use, so it is done by hand: add the domain to the service, add it to the service'sDJANGO_ALLOWED_HOSTS(after thetitangroup's value), and setSITE_URL=https://traintrackr.liveandFIVEBAR_DOMAIN=traintrackr.livein thetraintrackergroup. titan never overwrites a value that is already set, soDEFAULT_FROM_EMAILcan be changed there too.Add the server as a claude.ai connector (below).
Add as a claude.ai connector
/mcp is Titan's MCP view behind mcp-auth, the template's OAuth server on django-oauth-toolkit, so it can be added once in claude.ai and used from claude.ai, Claude Desktop and the mobile apps. ChatGPT connects the same way.
In claude.ai: Settings → Connectors → Add custom connector, name
traintracker, URLhttps://<your-service-host>/mcp. Leave the OAuth client fields empty: Claude registers itself.Claude opens the server's sign-in page. Sign in (see Sign-in).
Signing in hands Claude a one-hour access token and a 30-day refresh token, rotated on each refresh. The offline_access scope is listed, which ChatGPT needs to stay connected when its access token expires. Only callbacks to Claude, ChatGPT and loopback addresses (desktop clients such as Claude Code) are accepted (MCP_AUTH in config/settings.py). Anyone with an active account may connect. /oauth/connected/ lists the apps connected to the signed-in account. The traintracker-purge cron job deletes expired tokens each night.
Sign-in
Sign-in is Titan's accounts: an email address, then the link or the six-digit code in the email it sends, or a passkey added from the account page. There are no passwords. docs/accounts.md has the details: how long a link and a code last, the limits on emails and code tries, what an account keeps, and how to close or forget one. With DJANGO_DEBUG=1 the sign-in email is written to the console log in place of being sent; don't use that on a host whose logs other people can read.
Rate limit. Tool calls on /mcp are limited per account: RATE_LIMIT_BURST calls at once, refilled at RATE_LIMIT_PER_MINUTE. One Darwin key serves every user, and the limit stops one account spending the whole allowance. A call pays for one request to Darwin; a call that makes more (a long board read page by page, a journey with several legs) is charged one for each further request, so the account's next calls wait longer. A journey plan counts as three calls. A call over the limit comes back as a tool error, Too many requests. Try again in N seconds., which the model can read and relay. The counts are held in memory, so a restart clears them. serve_stdio is not limited.
Site
The Django app also serves a small public site, so there is one deploy and one domain:
Path | Page |
| What the server does, the connector address with a copy button, how to add it to Claude and ChatGPT, three example prompts |
| Each tool in plain English, three worked examples with what the answer contains, the limits, data sources, support |
| Privacy policy (UK GDPR): what is processed, why, for how long, and by whom |
| Terms of use: the service as is, accuracy, liability, fair use, data licences, governing law |
| Pick a station, and a platform if you like, for a live board (see Shareable boards) |
The site is apps/public/. The pages are Django templates: each page's content is a fragment in templates/public/pages/ (index.html, docs.html, privacy.html, terms.html) placed inside templates/public/layout.html, rendered by views.py; pages.py lists them, builds the footer's links, and turns the privacy page into the text the privacy_policy tool returns. The shareable boards (the board pages, the picker, the embed, the TV view, the JSON feed and the station suggestions) are rendered per request by boards.py; frame.html is the board alone, for an embed or a TV. The static files are in static/: one stylesheet, css/site.css, and one script, js/site.js, for the copy buttons, the departure boards and the station picker. The board is the app's look, drawn by site.js from a table of example trains in index.html: apps/rail/ui/board.html keeps its style and script inline, which the site's content security policy refuses, so the flaps are written out again in site.css and site.js. A change to how the app draws its flaps goes in both. The icon is static/icons/icon.svg, with PNGs rendered from it at 32, 180 and 512 pixels; icon-512.png is the one uploaded to the directory listings, and /favicon.ico redirects to the 32-pixel PNG. To change the icon, edit the SVG and render the PNGs again, for example magick -background none -density 1200 icon.svg -resize 512x512 PNG32:icon-512.png. The link-preview card is static/img/share.png, 1200 by 630, drawn from static/img/share.svg: the front page's promise beside the departure board app. It needs a browser to render: the card uses the system's sans-serif and bold monospace fonts, which ImageMagick's own SVG renderer can't select. Draw share.svg onto a 1200 by 630 canvas in a browser and save that as a PNG, or take a screenshot of it at that size with a device pixel ratio of 1; then magick saved.png -strip PNG24:share.png drops the alpha channel, which the tests reject. In share.svg each flap is a <rect> and each letter its own <text>, so changing a train means changing its letters one by one. There is no build step. The pages name the server's own values (the connector address from SITE_URL, the fair-use line from RATE_LIMIT_PER_MINUTE and RATE_LIMIT_BURST), so a copy deployed elsewhere describes itself. The privacy policy and terms name this repository's deployment and its operator: change privacy.html, terms.html and the support address when you deploy your own.
The stylesheet and script are served by WhiteNoise under names that carry a hash of the file (collectstatic), so a browser fetches a changed file at once and can cache an unchanged one. The pages set no cookies and load nothing from another origin, except fivebar's counter while FIVEBAR_DOMAIN is set; the Content-Security-Policy header allows only the site's own stylesheet, script and fetches. They follow the reader's light or dark setting and work at phone width.
Shareable boards
/board/LST is a station's live departures as a page of its own, /board/LST/9 one platform's, and /board/LST/COL the trains calling at Colchester: the homepage's split-flap board with live trains and a station clock, to keep open on a screen, share as a link or embed in another site. Nobody has to sign in. /board is a form to pick the station, and a destination or a platform; the station fields suggest names as you type.
Address | What it is |
| Every departure from London Liverpool Street in the next two hours, up to 10 |
| Departures from platform 9 only; a train whose live platform isn't announced yet is matched on its booked one |
| Departures calling at Colchester, wherever they end: the Norwich trains too |
| The board alone, filling a TV screen: see below |
| The same board alone, with no site header or footer, for an |
| The board as JSON, which the page fetches every minute while it is visible |
After the station, a station's three-letter code is a destination and anything else a platform. A board is for a destination or a platform, never both. Each board has one address: a lower-case code, a name (/board/cambridge, /board/LST/colchester) or a platform written p9 or platform-9 redirects to it, so every share of a board is the same link. A name that fits several stations goes to the picker, which asks which. The board page has the link and the <iframe> code, each with a copy button, and a link to each platform's board.
The page is rendered with the trains in it, as a table, so it works without JavaScript; site.js draws the flaps, which turn from the old letters to the new at each update. Because anyone can open a board, and a board embedded in a busy page is opened by all its visitors, what reaches Darwin is one fetch per board a minute, not one per viewer: an answer (or a failure) is kept for 60 seconds and shared by every request for that board (SharedBoards in board.py), and requests that arrive while it is being fetched wait for the same answer. Each client address may open 30 boards at once and 60 a minute (BOARD_LIMIT in apps/public/board.py); over that the answer is 429 with Retry-After. The boards count toward DARWIN_DAILY_LIMIT like any other request.
On a TV. ?tv=1 shows the board alone and sizes its flaps so that every train fits the screen, in one line a train on a wide screen and two on a tall one; the columns the screen has left over at that size widen the destination, so the board fills the width and long names fit. On the board page, Show on TV switches to the same view in place and goes full screen, for a window dragged onto a TV used as an extended display or a cast tab; leaving full screen goes back. On a TV the screen is kept awake (Screen Wake Lock, where the browser has it), the cursor hides after 3 seconds without moving, and the page reloads itself once a night, between 03:10 and 03:50 UK time, so a board left running for weeks picks up changes to the site. It shares its fetch with every other view of that board, so it costs Darwin nothing extra. Every live board counts down to its next update beside "Updated", and one that hasn't updated for 5 minutes dims and says when it last did.
MCP Registry
server.json describes the server for the official MCP Registry: the name live.traintrackr/traintracker, the version, and one remote, streamable HTTP at https://traintrackr.live/mcp. It follows the registry's 2025-12-11 schema. A test keeps its version in step with pyproject.toml.
Version 0.1.0 is published. CI doesn't publish: a new version is published by hand, with mcp-publisher login dns and then mcp-publisher publish. A live.traintrackr/ name needs proof that you hold the domain, which is a TXT record on the apex of traintrackr.live carrying the public half of the signing key. For your own deployment, change the name and the URL to your domain.
Limitations
Past running times ("was the 08:00 late yesterday?") aren't available. Darwin only covers now → +2 hours, and the timetable is booked times.
Darwin outages: when Darwin is offline, the live tools show booked times and say that Darwin is offline, so delays, cancellations and live platforms are missing until it returns.
Fares aren't included.
Tube/bus/tram aren't in the timetable beyond the approximate London terminal links.
Engineering works appear in the timetable once Network Rail publishes them (usually well ahead), and in Darwin on the day.
Development
Traintrackr is a Django project on Titan, the project template its sibling apps are built from. It moved onto Titan in four steps, from a Starlette app of its own (the decision); keep new work close to the template so copier update --trust stays a clean merge. HTTP is served by Django under gunicorn, with the train tools on one event loop per process (the decision).
tox runs every check on Python 3.14 from uv.lock (via the tox-uv plugin), as Titan does; docs/testing.md says which test goes where. The rail tests (tests/rail/) need a Postgres they can create schemas in, at TEST_DATABASE_URL (default postgresql://postgres:postgres@127.0.0.1:55432/postgres, which the docker run under Install provides). Each test works in its own schema and drops it afterwards (tests/rail/conftest.py). CI runs Postgres 17 as a service.
uvx --with tox-uv tox # fmt, lint, types, checks, test, audit
uvx --with tox-uv tox -e test # one environment
uvx --with tox-uv tox -e test -- -k platform # arguments after -- go to the tool
uvx --with tox-uv tox -e sast # semgrep (downloads its rule packs)CI (.github/workflows/ci.yml) runs each environment as its own job, with sast and a gitleaks scan as well, using the versions of uv, tox and tox-uv written into the workflow, and its Actions pinned to a commit. Dependabot (.github/dependabot.yml) proposes updates to uv.lock and to the Actions each week; the uv and tox versions are raised by hand, uv in render.yaml as well. uv run pre-commit install runs ruff, gitleaks and mypy before each commit.
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Tests use a synthetic SCHEDULE feed in Network Rail's JSON format (tests/rail/feedgen.py) and API fixtures shaped on the published Darwin schema. They aren't live recordings, so the first run against real services is the final check.
Preview servers
.claude/launch.json has two servers that Claude Code's preview pane can start. Both run in demo mode against the development Postgres above, ignore .env, and listen on 127.0.0.1 only. Set PREVIEW_DATABASE_URL to use another database.
Name | Runs | Use it for |
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| The public site, the sign-in pages and |
| The MCP Inspector (version 2, through | Calling the tools by hand. Its Apps tab draws a tool's MCP App, where it has one |
The Inspector needs Node 22.19 or later. It starts a local server that can run commands, guarded by a token it makes at each launch and puts into the page it serves; the config leaves that on.
manage.py
config/ Settings (one module, from the environment), URLs, WSGI/ASGI
apps/
core/ Titan's shared pieces: BaseModel, idempotency, rate limits, /livez and /healthz
accounts/ Sign-in by email link or code, passkeys, the account commands
mcp/ /mcp: Titan's MCP view (mcp-auth), the tool list, ui:// resources
public/ The site: pages (views.py, pages.py), boards (boards.py, board.py), templates
pwa/ The app's name and identity, as Titan's templates use it
rail/ The train tools and the data behind them
server.py MCP tools, source fallback, live overlay
runtime.py The tools' event loop, one per process
timetable.py SCHEDULE importer and Postgres queries (STP resolution)
planner.py Connection Scan journey planner, London links
darwin.py Rail Data Marketplace LDBWS client
usage.py Count of requests sent to Darwin, against the allowance
ratelimit.py Per-account limit on tool calls
stations.py Station search and name resolution
trainline.py Links to a train's page on Trainline
schemas.py Output models shared by all sources
demo.py Demo mode: generated timetable and in-process Darwin
config.py The train tools' settings, from the environment
ui/ MCP App: the departure board (ui://traintracker/board.html)
data/ stations.json, trainline_slugs.json
management/ serve_stdio, refresh_timetable, import_timetable, rail_status
templates/ Traintrackr's sign-in, account and connect pages
static/ site.css, site.js, the sign-in scripts, the icons and the share card
tests/ core, accounts, mcp, public, rail
docs/ accounts.md, testing.md, decisions/Data and licences
Darwin data via the Rail Data Marketplace, and Network Rail data feeds, are used under the terms you accept when you subscribe. Check those terms before redistributing any output. Both ask for the source to be credited:
Data | Credit | Where the wording comes from |
Darwin (live times) | "Powered by National Rail Enquiries", with a link to nationalrail.co.uk and the logo from the NRE Brand Guidelines | NRE Developer Guidelines v06-01, section 4. Where the feed is combined with other data, the credit may go on an attribution page |
Network Rail SCHEDULE (timetable) | "Contains public sector information licensed under the Open Government Licence v3.0." | The Network Rail data feeds licence releases the feeds under the Open Government Licence v3.0 and gives no statement of its own, so the licence's default applies |
Station list | davwheat/uk-railway-stations, Open Database License (ODbL) | The repository's licence |
The credits are on /docs, under "Where the data comes from". The footer of every page of the site carries the National Rail Enquiries credit and a "Data sources" link to that section. The server's instructions carry one line naming the sources, so an assistant can credit them when it says where an answer comes from; tool responses are not padded with it. The footer has the words and the link but not the NRE logo: the brand pack on the Darwin data feeds page makes the logo's use subject to National Rail's permission, which was asked for on 2026-09-30 (TODO(hugo) in layout.html).
Code: MIT.
Available Tools
9 toolsdata_statusBInspect
Which data sources are configured, how fresh the timetable is, and what to set up.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
Output Schema
| Name | Required | Description |
|---|---|---|
No output parameters | ||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It clearly conveys that this is an introspection/status tool covering three specific facts, which implies a read-only nature. However, it does not state whether authentication is required, whether it calls external systems, or any side effects. It adds useful context but omits behavioral details.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single sentence and wastes no words, front-loading the main point about data source configuration. The phrasing is slightly awkward ("what to set up" is a bit unclear), but the overall length and structure are appropriate for the tool's simplicity.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given zero parameters, an output schema, and low complexity, the description covers the essential purpose well: it names the three kinds of information the tool provides. It does not need to explain return values because an output schema exists. The only missing element is a brief note on when the status should be checked, which is a usage-guidance gap rather than a completeness failure.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool has zero parameters and the schema coverage is 100%, so there is nothing for the description to add on parameter meaning. Per the baseline for a parameterless tool, this scores a 4. The description correctly avoids inventing parameters that do not exist.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states what the tool reports: configured data sources, timetable freshness, and setup instructions. While the verb is implicit rather than explicit ("get" or "show" is missing), the resource and scope are specific enough to distinguish it from the travel-data siblings. It could be stronger with an explicit verb, but it is not vague or tautological.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives no guidance about when to use this tool versus alternatives. The sibling tools are clearly about live travel data, so context implies that data_status is for configuration and health checks, but no when-to-use or when-not-to-use conditions are stated. An agent must infer the use case without explicit direction.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
departure_platformAInspect
Which platform one train leaves from. Live platforms are often announced only ~10 minutes before departure at large stations; until then the booked (timetable) platform is returned and flagged as 'booked'.
| Name | Required | Description | Default |
|---|---|---|---|
| to | No | Only trains calling at this station. | |
| time | No | Booked departure HH:MM (24h). Default: the next train. | |
| station | Yes | Station name or CRS code. |
Output Schema
| Name | Required | Description |
|---|---|---|
| note | Yes | |
| service | Yes | |
| station | Yes | |
| platform | No | |
| platform_source | No | |
| minutes_to_departure | No | From now to the expected (else booked) departure. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It explains the key behavioral nuance: before the live platform is announced, the booked timetable platform is returned and flagged as 'booked'. This is valuable context beyond a simple 'get platform' statement.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is brief and front-loads the core purpose, followed by an important timing caveat. It is slightly awkwardly phrased ('Which platform one train leaves from') but remains efficient and free of unnecessary filler.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given that an output schema exists and the parameter schema is fully described, the description covers the essential behavioral context. It explains the live-versus-booked distinction, which is the main nuance an agent needs. It could mention how the train is identified via station and time, but the schema already provides this.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the schema already documents all three parameters. The description does not add much parameter-level detail beyond what the schema provides, which is acceptable given the high coverage.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's purpose: returning the platform from which a single train departs. It also distinguishes the live vs booked platform behavior, which helps differentiate it from sibling tools like platform_departures, though it does not explicitly name any sibling.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides useful context about when live platforms become available (~10 minutes before departure) and that booked platforms are returned otherwise. However, it does not explicitly state when to use this tool versus alternatives such as platform_departures or live_departures, leaving some inference to the agent.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
find_stationBInspect
Look up GB railway stations by name or CRS code, best match first.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| query | Yes | Station name, partial name or 3-letter CRS code. |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must carry the behavioral disclosure. It does state that results are ordered by 'best match first', which is useful, but it omits other behaviors like case sensitivity, handling of partial matches, or error conditions. For a simple lookup, this is minimal but not severely lacking.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, front-loaded sentence that efficiently states the purpose and ordering behavior. No filler or redundant phrasing.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's low complexity and the presence of an output schema, the description is adequate but not rich. It covers the core lookup behavior but does not mention result format, case sensitivity, or limit semantics. For a straightforward station lookup, it is minimally complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 50%: the query parameter has a description, but limit has none. The tool description reiterates that query accepts name or CRS code, adding little beyond the schema. It provides no clarification for the limit parameter, leaving it underspecified.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool looks up GB railway stations by name or CRS code and returns best match first. This specifies a verb, resource, and search criteria, but it does not explicitly differentiate from sibling tools like live_departures or plan_journey, so it misses the top score.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance is given on when to use this tool versus alternatives. The description implies it is for station lookup, but there is no explicit mention of when to prefer it over other tools or any exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
live_arrivalsBInspect
Live arrivals for the next ~2 hours. Uses Darwin's arrivals product if configured, then RTT, then booked timetable times.
| Name | Required | Description | Default |
|---|---|---|---|
| rows | No | ||
| station | Yes | Station name or CRS code. | |
| from_station | No | Only trains that called at this station earlier. | |
| include_calling_points | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| date | Yes | |
| board | Yes | |
| filter | No | |
| source | Yes | |
| station | Yes | |
| messages | No | Station/network alerts. |
| services | Yes | |
| platform_available | No | False if the live feed publishes no platforms for this station. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden. It discloses a meaningful data-source precedence and that results are approximated to the next ~2 hours. This is beyond what the schema or annotations would show, though it leaves other live-data behaviors (update cadence, cancellation handling) unstated.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences deliver the core purpose and the data-source fallback with no filler. The main limitation is jargon ('RTT'), but the structure itself is appropriately sized and front-loaded.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The presence of an output schema excuses return-value detail, and the description covers purpose and behavior. However, it does not orient the agent relative to the sibling tools or explain the acronym, leaving moderate context gaps for a 4-parameter tool with no annotations.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The description adds no parameter-level semantics; station, rows, from_station, and include_calling_points are left entirely to the schema. Schema description coverage is only 50%, so the description should compensate for the undocumented parameters but does not.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description identifies the resource ('arrivals') and the time window ('next ~2 hours'), and the tool name reinforces a station-level live arrivals lookup. It stops short of a verb form and does not explicitly contrast with live_departures, so it loses a point.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No when-to-use guidance is provided. The fallback chain ('Darwin's arrivals product if configured, then RTT, then booked timetable times') describes data sourcing, not when to choose this tool over live_departures, timetable, or service_details. None of the sibling tools are mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
live_departuresAInspect
Live departure board for the next ~2 hours: expected times, platforms, delays, cancellations. Uses Darwin (National Rail); falls back to RTT or the timetable.
| Name | Required | Description | Default |
|---|---|---|---|
| to | No | Only trains calling at this station. | |
| rows | No | ||
| station | Yes | Station name or CRS code. | |
| offset_minutes | No | Shift the board start (e.g. 30 = from +30 min). | |
| include_calling_points | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| date | Yes | |
| board | Yes | |
| filter | No | |
| source | Yes | |
| station | Yes | |
| messages | No | Station/network alerts. |
| services | Yes | |
| platform_available | No | False if the live feed publishes no platforms for this station. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the transparency burden. It usefully discloses the ~2-hour window, the types of information returned, and the data-source fallback chain, which are meaningful behavioral traits beyond the schema.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is compact and front-loaded: it states the core purpose first, then adds a concise data-source note. Every sentence earns its place with no redundant wording.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description covers core behavior and data provenance, and an output schema exists, so return structure is not a gap. However, it lacks sibling differentiation and does not compensate for the undocumented parameters, making it only partially complete for a 5-parameter tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 60%, so the schema already explains several parameters. The description adds a time-window frame but does not clarify rows, include_calling_points, or how offset_minutes interacts with the board, leaving some parameter semantics under-specified.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly identifies a live departure board with a specific time horizon and output content (expected times, platforms, delays, cancellations). It is distinct from live_arrivals, though it does not explicitly differentiate itself from departure_platform or platform_departures.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No explicit guidance is given about when to use this tool over siblings like live_arrivals, platform_departures, or timetable. The mention of Darwin/RTT/timetable fallback provides data-source context but not usage routing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
plan_journeyAInspect
Plan journeys between two stations, with changes up to max_changes. Returns the fastest options first plus the fewest-changes option. Cross-London transfers between terminals are included as approximate walk/Tube links. For today's trains in the next two hours, live Darwin times are added and at-risk connections flagged.
| Name | Required | Description | Default |
|---|---|---|---|
| via | No | Force a change at this station. | |
| date | No | YYYY-MM-DD, 'today' or 'tomorrow'. | |
| live | No | Overlay Darwin live times for today. | |
| time | No | Depart at or after HH:MM. Default now. | |
| count | No | ||
| origin | Yes | Start station name or CRS code. | |
| destination | Yes | End station name or CRS code. | |
| max_changes | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| notes | No | |
| origin | Yes | |
| journeys | Yes | |
| destination | Yes | |
| searched_from | Yes | |
| interchanges_considered | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral burden. It discloses meaningful operational traits: results are ordered fastest-first, cross-London transfers are approximate walk/Tube links, live Darwin times are only added for today's trains within the next two hours, and at-risk connections are flagged. This goes beyond a typical terse description, though it does not address read-only/side-effect behavior explicitly.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three sentences, each earning its place: the core purpose, the output ordering and approximation caveat, and the live-data behavior. It is front-loaded with the most decision-relevant information and contains no filler or repetition.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity, the description covers the essential choices an agent must make: output ordering, change limits, cross-London transfer approximations, and live data conditions. The presence of an output schema relieves the description of explaining return fields in detail. It is slightly incomplete only in not clarifying count's meaning and not naming sibling alternatives, but it is otherwise robust.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 75%, so most parameters are already documented. The description adds useful prose meaning for max_changes and live, but count remains undocumented in both the schema and the description, leaving its role as the number of returned journey options implicit rather than explicit. This partial compensation keeps it at the baseline rather than above it.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description opens with a specific verb and resource: 'Plan journeys between two stations, with changes up to max_changes.' It also states the output ordering and the fewest-changes option, clearly differentiating it from sibling tools like live_departures and timetable, which cover station departures or single services rather than end-to-end journey planning.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives clear context: use this tool when a journey between two stations is needed, including changes and cross-London transfers. It does not explicitly name alternatives or state when not to use it, so it stops short of the highest bar, but the intended use case is unmistakable.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
platform_departuresAInspect
The next trains leaving from one platform in the next ~2 hours. A train whose live platform isn't announced yet is matched on its booked platform (platform_source 'booked'), which can still change.
| Name | Required | Description | Default |
|---|---|---|---|
| count | No | ||
| station | Yes | Station name or CRS code. | |
| platform | Yes | Platform, e.g. '4' or '9B'. |
Output Schema
| Name | Required | Description |
|---|---|---|
| date | Yes | |
| board | Yes | |
| filter | No | |
| source | Yes | |
| station | Yes | |
| messages | No | Station/network alerts. |
| services | Yes | |
| platform_available | No | False if the live feed publishes no platforms for this station. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral transparency burden. It usefully discloses the live-vs-booked platform matching logic and the caveat that a booked platform can change. It doesn't cover every possible behavioral aspect like authentication or error cases, but for a simple read-style query tool this is strong disclosure.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences with no filler. The primary scope and time window are front-loaded, and the important matching caveat is added in the second sentence. Every part earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The core domain nuance (platform assignment can change) is disclosed, and an output schema exists to define return values. It could be more explicit about choosing this over related sibling tools, but for a single-platform departure query it provides enough context for correct selection and invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The schema already documents 'station' and 'platform' with meaningful descriptions, while 'count' has constraints but no explicit semantic description. The tool description adds no parameter-level detail beyond what the schema provides, and schema coverage is moderate at 67%, so this is adequate but not enriched.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific resource ('one platform') and behavior ('next trains leaving') with a clear time horizon ('next ~2 hours'). This distinguishes it from sibling tools like live_departures, which imply station-wide departures, and departure_platform, which focuses on determining a train's platform.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description clearly implies usage: use this when you need departures from a specific platform within about two hours. However, it does not explicitly state when not to use it or name alternatives such as live_departures or departure_platform, so the guidance is implied rather than prescribed.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
service_detailsAInspect
All stops for one train, with live times where available.
| Name | Required | Description | Default |
|---|---|---|---|
| service_id | Yes | A service_id from another tool (darwin:…, tt:… or rtt:…). |
Output Schema
| Name | Required | Description |
|---|---|---|
| date | No | |
| mode | No | |
| origin | Yes | |
| reason | No | |
| source | Yes | |
| headcode | No | |
| operator | No | |
| cancelled | No | |
| service_id | Yes | |
| destination | Yes | |
| calling_points | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It does disclose the key caveat that live times are only provided 'where available' and implies a read-only lookup. However, it does not address failure behavior, data source freshness, or whether historical services are supported; the output schema covers return structure.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single sentence with the core purpose front-loaded and the live-times caveat appended. Every word earns its place, and there is no redundant or filler content.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a one-parameter read tool with an output schema, the description plus schema is largely sufficient for an agent to call it correctly. The only notable gap is the lack of explicit usage guidance relative to sibling tools, but that is already captured in the usage_guidelines dimension.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, and the parameter description already explains the accepted service_id formats. The tool description adds no new parameter-level meaning beyond implying the ID identifies a train service, so the baseline of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly identifies the resource ('one train') and the content ('all stops'), and the 'live times where available' qualifier distinguishes it from a static timetable. It lacks an explicit verb, but the intent is unambiguous and it is easily differentiated from siblings like live_departures and timetable.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The phrase 'for one train' implies when to use this tool, but there is no explicit guidance on when to prefer it over alternatives such as timetable or live_departures. No exclusions or alternative tool names are mentioned, leaving the agent to infer the appropriate context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
timetableAInspect
Booked train times at a station for any date the timetable covers (usually months ahead). Use for future trips; for right now prefer live_departures.
| Name | Required | Description | Default |
|---|---|---|---|
| to | No | Only trains later calling here. | |
| date | No | YYYY-MM-DD, 'today' or 'tomorrow'. | |
| rows | No | ||
| time | No | Start time HH:MM (24h). Default: now today, else the whole day. | |
| board | No | departures | |
| station | Yes | Station name or CRS code. | |
| from_station | No | Only trains earlier calling here. | |
| window_minutes | No | ||
| include_calling_points | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| date | Yes | |
| board | Yes | |
| filter | No | |
| source | Yes | |
| station | Yes | |
| messages | No | Station/network alerts. |
| services | Yes | |
| platform_available | No | False if the live feed publishes no platforms for this station. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden, and it does add meaningful context: 'booked' signals this is the planned timetable rather than real-time, and the horizon ('usually months ahead') is disclosed. However, it does not say how out-of-coverage dates are handled, whether live disruption is reflected, or what the response shape implies, so the behavioral disclosure remains partial.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two short sentences with zero filler. Purpose and scope are front-loaded first, and the usage caveat follows immediately; every word earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
An output schema exists, so return values need no explanation. The description handles the primary use case well, but for a 9-parameter tool it leaves unaddressed the arrivals board, row/window controls, and calling-point behavior, relying on the schema to carry those details.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 56%, so the description is expected to partially compensate. It reinforces the two core parameters ('at a station' for station, 'any date the timetable covers' for date) and adds the horizon semantics. But rows, window_minutes, include_calling_points, and board have no schema descriptions and the description offers nothing for them, so the gap persists.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description opens with a specific verb and resource ('Booked train times at a station') and clarifies the temporal scope ('any date the timetable covers, usually months ahead'). It explicitly differentiates from the closest sibling by pointing to live_departures for real-time queries, so an agent can tell them apart without opening schemas.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives clear when-to-use guidance ('for future trips') and an explicit when-not-to with a named alternative ('for right now prefer live_departures'). It does not, however, address other overlapping siblings such as live_arrivals (given the board=arrivals option) or plan_journey, leaving some routing to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
9 tool updates
v0.1.0- First observed
data_status - First observed
departure_platform - First observed
find_station - First observed
live_arrivals - First observed
live_departures - First observed
plan_journey - First observed
platform_departures - First observed
service_details - First observed
timetable
TDQS
Scored across 9 tools
Each tool targets a distinct station/service/platform resource, and the descriptions clearly separate live departures, platform departures, and a train's platform. The main risk is the departure_platform/platform_departures name pair, which could be confused, but the descriptions disambiguate them well.
Names are consistently snake_case and readable, but they mix noun-style resources (timetable, service_details, data_status) with verb-style actions (plan_journey, find_station). The departure_platform/platform_departures swapped-word pair also breaks a clear naming pattern.
Nine tools is well-scoped for a UK rail information server. Each tool covers a meaningful query type without bloat, and the set feels appropriately sized for both departure boards and journey planning.
The read-only rail domain is well covered: station lookup, live arrivals/departures, platform data, future timetable, per-service details, and journey planning are all present. The data_status tool also gives agents a way to diagnose missing or stale data sources, avoiding dead ends.
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