Stone — Terms of Service

Last updated: 2026-08-27. Version 2026-08-27.

These terms cover your use of Stone, an iOS and watchOS training app. They are written to be read, not to be survived. If something here is unclear, that is a defect — say so and it gets fixed.

Who this agreement is with

Stone is made by an independent developer. "We", "us" and "Stone" mean the developer and the app. "You" means the person using it.

Using Stone means you accept these terms. If you do not accept them, do not use the app.

What Stone is, and what it is not

Stone is a workout log and a training assistant. It records what you lift, looks at your history, and suggests what to do next.

Stone is not a medical device and not a clinician. It does not diagnose, treat, or prevent anything. Its suggestions are exactly that — suggestions from software that has seen your training log. Do not use them in place of advice from a qualified professional. The Health Disclaimer covers this in full and is part of these terms.

Training carries risk of injury. You are responsible for deciding what is safe for your body on any given day, for your own technique, and for stopping when something is wrong. Stone will sometimes suggest a load or a session that is wrong for you. Treat every suggestion as a starting point you are free to ignore.

Your account

Sign in with Apple is optional. You can use Stone without an account; signing in raises your daily AI limits and lets your data sync through your own iCloud.

You are responsible for keeping access to your Apple ID secure. You can delete your account and all associated data at any time from Settings ▸ Privacy ▸ Delete all my data. That deletion is real and it is not reversible.

Your data is yours

Stone claims no ownership of what you put into it. Your workouts, notes, custom exercises and conversations with the coach belong to you.

Where that data lives, what leaves your device, and who can see it, is set out in the Privacy Policy and the AI Disclosure. Both are part of these terms.

You can export everything, in a readable format, from Settings ▸ Privacy.

The AI features

Cloud AI is off until you turn it on. With it on, some of what you write and log is sent to a third-party model provider to produce a reply. What is sent, and what the provider does with it, is described in the AI Disclosure.

AI output is generated text. It can be wrong, out of date, or confidently mistaken. It is not reviewed by a human before you see it. Judgement remains yours.

There are daily limits on AI use, and they can change. They exist so one person cannot exhaust a shared budget.

Acceptable use

Do not use Stone to break the law, to attack the service, or to work around its rate limits, device checks or quotas. Do not attempt to extract other people's data. Automated or scripted use of the AI endpoints is not permitted.

If you do these things, access can be suspended.

Paid features

Stone may offer paid features. If it does, this is how it works:

• Purchases are made through Apple's In-App Purchase system. Apple processes the payment; we never see your payment details.
• A subscription renews automatically until you cancel it. You cancel in the App Store, under your Apple ID subscriptions — not in Stone, because Apple does not permit it there.
• Refunds are handled by Apple, under Apple's policy, not by us. We cannot issue or deny a refund for an App Store purchase.
• If you have paid and the app does not recognise it — a new phone, a reinstall, a restored backup — use Restore Purchases. It asks Apple what you own and re-applies it. It never charges you.
• Prices can change. A change never applies to a period you have already paid for, and Apple notifies you before a renewal at a new price.

Nothing you have already paid for is taken away by a change to these terms.

Availability

Stone is provided as-is. It can be unavailable, lose features, or stop being developed. The AI features depend on a third-party provider and can fail or be withdrawn independently of the rest of the app.

Your logged data is stored on your device and, if you enable sync, in your own iCloud account — so it does not disappear if the service does. Keep your own export if that matters to you.

Liability, in plain terms

To the extent the law allows: Stone is not liable for injury, lost data, lost progress, or any indirect or consequential loss arising from your use of it. Where liability cannot be excluded, it is limited to what you have paid for Stone in the twelve months before the claim.

Some jurisdictions do not allow these exclusions. Where that is the case, they do not apply to you and you keep whatever rights your local law gives you.

Changes

These terms can change. Material changes will be surfaced in the app. The version stamp at the top of this document is what identifies a revision; each AI request Stone makes records the policy version that applied at the time, so your own history stays pinned to the terms that were in force when it happened.

Continuing to use Stone after a change means accepting the revised terms.

Ending this

You can stop using Stone at any time, delete your data from Settings ▸ Privacy, and remove the app. We can end access if these terms are broken.

Sections that by their nature should survive — your data rights, liability, and the disclaimers — survive termination.

Contact

Support and contact details are on the Stone support site. During the beta the fastest route is TestFlight feedback, which reaches the developer directly.