What it returns

Field	Meaning
days	Lookback window in days, counted back from now. Ignored when `start` is given.
start	Start of the range, ISO-8601 (e.g. '2026-08-01'). Overrides `days`.
end	End of the range, ISO-8601. Defaults to now.

Parameters

Name	Type	Description
`days`	`integer`	Lookback window in days, counted back from now. Ignored when `start` is given.
`start`	`string`	Start of the range, ISO-8601 (e.g. '2026-08-01'). Overrides `days`.
`end`	`string`	End of the range, ISO-8601. Defaults to now.

Pass either days or an explicit start/end pair. start wins if both are given.

Output

A markdown table rather than JSON — roughly a third of the tokens, and models reason over rows more reliably than nested objects.

Notes and gotchas

Requires a connected Withings account. Connect it from your dashboard — no developer account needed.
Read-only: this tool cannot change anything in your account.

Call it directly

The endpoint is plain JSON-RPC, so you can test without any client:

curl

curl -s https://fitnesspeak.app/mcp \
  -H "Authorization: Bearer fp_live_YOUR_KEY_HERE" \
  -H "Content-Type: application/json" \
  -d '{
       "jsonrpc": "2.0",
       "id": 1,
       "method": "tools/call",
       "params": {
         "name": "withings_sleep",
         "arguments": {
           "days": 7
         }
       }
     }'

Tool description the model sees

Nightly sleep from a Withings Sleep Analyzer, sleep mat or watch: time in bed, time asleep, light / deep / REM duration, efficiency, latency, wake-ups, heart and respiratory rate, snoring and sleep score. Call this when the user asks how they slept, about sleep quality or sleep stages, or wants to compare nights. If they also have WHOOP, whoop_sleep covers the same ground from the strap.

Descriptions say when to call a tool, not just what it does — that trigger wording is what models actually route on.

`withings_sleep`