How the relay actually works
Start with the honest part, because it is the whole point. There is no direct link between Withings and Wellness Project, and there is no Withings MCP server you connect to. Your Withings scale, watch, sleep mat, or blood pressure cuff talks to the Withings Health Mate app, and Health Mate writes those readings into the health hub already built into your phone: Apple Health on iPhone, Google Health Connect on Android.
Wellness Project reads that hub. It takes the weight, body composition, blood pressure, sleep, and heart rate Withings deposited there, structures them into one continuous history, and serves that history to Claude and ChatGPT over a single MCP connection. So the real chain is Withings to Apple Health or Health Connect, then Wellness Project, then Claude or ChatGPT. We never touch Withings directly, and we do not pretend to.
Why go through the hub at all
Routing through Apple Health or Health Connect is not a workaround, it is the sturdier design. The hub is the one place Withings already maintains a permission to write to, so there is no extra token to babysit and nothing to re-authorize every few weeks. When Withings ships an app update, your data keeps flowing because the contract is between Withings and the phone, not between Withings and us.
It also means every other device you own can join the same history. The Withings scale reports your morning weight, an Apple Watch or Garmin reports the workout, an Oura ring reports the sleep, and they all land in the same hub. Wellness Project reads the whole picture, so your AI coach sees body composition next to training load next to recovery, instead of one number in isolation.
Set it up in four steps
The setup is short because the phone does the heavy lifting. Name the hub first, let Wellness Project read it, then point Claude or ChatGPT at your account.
Sync Withings into your phone hub
Open Withings Health Mate and confirm it is writing to the hub on your phone. On iPhone, that is Apple Health: allow Health Mate to write weight, body composition, blood pressure, sleep, and heart rate. On Android, that is Google Health Connect: grant the same categories, knowing blood pressure support in Health Connect is limited and may not carry over as cleanly as on iOS. The hub is the intermediary that holds everything Withings measures.
Let Wellness Project read the hub
In the Wellness Project app, grant Apple Health or Health Connect permission. It reads what Withings deposited and structures it into one history: weight trend, body-composition changes, blood pressure readings, and sleep, all keyed to your baseline. This is a read of the hub, not a connection to Withings.
Add the MCP connector to Claude or ChatGPT
Add the Wellness Project connector to Claude (via MCP) or ChatGPT (via the plugin). One connection is all it takes, and it covers everything in your hub, not just Withings. Claude and ChatGPT are the two AI integrations Wellness Project supports today.
Ask about your body data
Ask Claude or ChatGPT how your weight is trending, whether your body composition moved this month, or how your blood pressure readings compare to last quarter. It answers from your structured history, not a single reading.
That is the entire flow. No Withings login on our side, no real-time promise we cannot keep. Freshness tracks whenever Health Mate syncs to your hub, and Wellness Project reads it from there.
The platform caveat, stated plainly
iOS and Android are not equal here. On iPhone, Withings routes through Apple Health and the full set carries over, including blood pressure. On Android, Withings routes through Google Health Connect, where weight, body composition, and sleep move reliably but blood pressure support is limited and can lag or not appear at all depending on your Health Mate version.
If blood pressure is your priority metric, an iPhone plus Apple Health is the cleaner path today. For weight and body composition, either platform works well. Whichever you use, you add exactly one connector to Claude or ChatGPT and read everything in one place.
Put your Withings numbers in front of an AI that remembers them.
Sync Withings to Apple Health or Health Connect, store it in Wellness Project, and let Claude or ChatGPT read your weight, body composition, and blood pressure against your baseline. Free during early access.