Analyse Garmin data with Claude

Garmin Connect shows you numbers. It does not answer questions. "Was my heart rate on Sunday's long run higher than usual at that pace?" is ten clicks and a comparison in your head in Garmin Connect. In a conversation with Claude it is one sentence — provided Claude can see your data.

That is exactly what the Tri-Train MCP server does: it makes your activities, health metrics and plans available to Claude without you exporting, uploading or typing anything.

What an MCP server is

MCP stands for Model Context Protocol, an open standard from Anthropic. It describes how a language model such as Claude accesses external tools and data. An MCP server is the other end: an address behind which tools sit that Claude can call — for example "give me every run since June" or "how was sleep last week".

Most Garmin MCP servers you find online have to be installed by you: a Python script on your computer that logs in with your Garmin password and only runs while the machine is on. Tri-Train is a hosted MCP server. There is nothing to install, no script, no API key. You enter one address in claude.ai and confirm once via OAuth.

How to connect Claude

1. Sign up for Tri-Train and connect Garmin and Strava in the settings. Both are optional, but without at least one source there is nothing to analyse.
2. In claude.ai open the settings, then Connectors, and add a custom connector. The address is https://tri-train.com/api/mcp.
3. Claude opens Tri-Train in your browser. You sign in and confirm the access. Done.

The connection runs over OAuth. Claude never receives your password, and you can revoke the access at any time under Connected apps in your settings — without deleting the connector in Claude.

What Claude can see

Once connected, Claude has 17 tools available. You never need to know their names; Claude picks the right one. The most important things behind them:

• Activities: every session from Garmin or Strava with duration, distance, pace or power, heart rate, elevation and training load (TSS). On request, the details of a single session with laps and zones.
• Statistics: weekly and monthly totals per sport, fitness (CTL), fatigue (ATL) and form (TSB).
• Health metrics from Garmin: sleep duration and stages, HRV, resting heart rate, Body Battery, stress.
• Your profile: thresholds such as FTP, threshold pace and threshold heart rate, your level, your weekly hours.
• Plans and notes: what is in your calendar and what you have noted on sessions.

All of it is limited to your account. Every tool filters on your user ID; other people's data is not reachable through the connector.

Questions worth asking

Garmin Connect answers the simple questions too. Claude becomes interesting where you want to relate two things to each other:

• "How did I sleep in the nights before the hard sessions of the last four weeks?"
• "Compare my heart rate at 5:00 min/km in July and in September."
• "Which weeks had more than 400 TSS, and how did my form develop afterwards?"
• "Show me every bike session over two hours averaging below 65 % of FTP."
• "What stands out about my long run on Sunday?"

Claude fetches the right data for each question itself and works with it. You do not get a table, you get an interpretation — and you can ask follow-ups.

Writing needs a second permission

Reading is the default. If Claude is supposed to create, move or delete sessions, it needs a second permission that you grant explicitly when connecting. That way a misunderstanding in conversation can never silently rebuild your calendar.

And if something does go wrong: every writing action is journalled. "Undo the last change" restores the previous state.

Where the limits are

• Claude sees the data Tri-Train has. Sync runs every 15 minutes; a session you finished two minutes ago may not be there yet.
• Raw data at full resolution — every GPS point, every second of heart rate — is not passed to Claude. It would be too much for a conversation and too little help for analysis; laps, zones and summaries are the better yardstick.
• Claude is not a doctor and not a coach who knows you. What it says is an analysis of your numbers, not a diagnosis.

And back onto the watch

The path runs both ways. What Claude plans for you, Tri-Train can push to your Garmin as a structured workout — with intervals, target zones and, for swimming, pool lengths instead of metres. What that looks like day to day is in the guide Create a triathlon training plan with Claude.