Tether — AI Health Sync

Your AI can read your health. We never can. Tether is the first health app built to be read by YOUR own AI agent — Claude Code, Hermes, OpenClaw, or anything that speaks MCP. Sleep, cycle, heart, activity: end-to-end encrypted on your iPhone, decrypted only on hardware you control. FOR YOUR AI (Tether Pro) • Plug your health into any MCP-capable agent — the same way agents connect to files and databases • Your agent sees sleep stages, cycle patterns, HRV trends, symptoms — and reasons across them • Decryption happens on YOUR machine only. No AI runs in our cloud. We store ciphertext, nothing else. FOR THE TWO OF YOU (free, forever) • Share sleep, cycle, weight, hydration with your partner — each category its own switch, controlled by the data owner • See each other's night at a glance; know when to be gentle • Dynamic Island shows whether your partner is still asleep PRIVATE BY PHYSICS, NOT BY PROMISE • Curve25519 + AES-GCM end-to-end encryption, keys in your personal iCloud Keychain • Cycle and symptom data: there is no readable copy on our side to leak, sell, or hand over • No ads. No data brokers. We couldn't train on your data even if we wanted to — we only have ciphertext. WHAT TETHER TRACKS Sleep (stages, heart rate), menstrual cycle with ovulation detection, 39 symptom types, weight, hydration, activity, resting heart rate, HRV, wrist temperature, workouts, mindfulness — from Apple Health and Apple Watch, or entered by hand. MEMBERSHIPS Recording and partner sharing are free forever. Tether Plus unlocks full history and trend charts. Tether Pro unlocks the AI agent interface (MCP) — monthly, yearly, or one lifetime purchase. Your use of Tether is governed by Apple's Standard EULA: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy policy: https://tetherme.app/privacy Support: https://tetherme.app/support