Case study01 / GRANITE

Granite

Rehab planning for physiotherapists — proposes and monitors, never clears. The same engine also coaches athletes whose sport isn’t lifting.

ServicesNative · On-device AI

Sitegranite.coach ↗

RoleDesign + build

StatusAlpha

Year2026

Now pilotingGranite Clinic ↗

Granite Clinic — the clinician's dashboard: patients who need attention first, each with a trend and a reason — The clinician’s view — three patients who need attention first

The work
01 / GRANITE

Granite is now piloting as a rehab-planning tool for physiotherapists: Granite Clinic proposes and monitors a patient’s plan between visits, and never clears them — that call stays with the clinician. The engine underneath is the one that already coaches athletes whose sport isn’t lifting: not a plan you follow, but reasoning that runs on fixed rules, not guesswork, entirely on-device. Every decision it makes can be traced, tested, and trusted — which is exactly what it takes to stand behind a plan someone else’s body depends on.

Granite Clinic — the review queue: a patient's proposed changes, the old set struck through, the new one next to it, with a reason for each — The clinician approves

Granite — a rehab exercise from the physio, pinned into the patient's normal session — The patient just trains

Fig. 01 · Granite Clinic · the loop, closedEvery change sits in a queue until a clinician approves it — the old set struck through, the new one next to it, with the reason attached. Approved, it shows up right inside the patient’s normal session. No second app, no portal to check.

The problem

A plan you cannot follow is worth nothing.

The week movesLife firstWork, sleep, travel, a niggle. The week you planned is rarely the week you get.

So the plan breaksMiss twoFixed programmes have no answer for a missed session, so people improvise or stop.

And nobody explainsNo reasonApps change your numbers without saying why, so there is nothing to trust or argue with.

One mechanism underneath all three: training adapts to the person, or the person quietly stops training.

Granite — the weekly rewrite, with the reasoning shown

Fig. 02 · Granite · the weekly rewriteMiss a few sessions, and it eases the week back — lighter, shorter, still complete — so you keep training instead of quitting, and don’t get hurt trying to catch up to where the plan says you should be.

Granite — a closer look: Barbell Row's old weight struck through, the new heavier weight next to it

Fig. 03 · Granite · the decision, closerThe same screen at reading distance. Every change is a decision you can trace back — the old number struck through, the new one next to it — because a coach you can’t interrogate is just a spreadsheet.

1For the person training

You do not need more discipline, you need a week that survives contact with your life. Granite rewrites it and tells you what changed.

2For the people who prescribe

Coaches and clinicians cannot stand behind a black box that will not show its reasoning. The same engine now also runs Granite Clinic, a separate product piloting with practising physiotherapists — it proposes and monitors a rehab plan between visits. It never clears.

A coach, not a plan

Most training apps hand you a fixed plan and hope you follow it. Granite works the other way round. It reasons — taking your goals, your experience, the days you actually have, your injuries, and the load you carry off the platform — and builds a week that fits your real life.

When something changes, it rewrites, and tells you why. Not a plan you obey. A coach that adapts.

Granite — telling the coach what changed this week — You say this

Granite — the same week after the note: Face Pull swapped for Band Pull-apart, External Rotation added — The plan changes

Fig. 04 · Granite · say this, the plan changesOne sentence about a sore shoulder, and the week changes around it — the exercise that would aggravate it swapped out, protective work added in. You keep training through the niggle instead of stopping, and nothing has to be re-entered by hand.

The engine is the product

Granite’s intelligence runs on fixed coaching rules, not AI guesswork — a deliberate choice, not a limitation. It means every plan is consistent, every decision can be traced, and the whole system can be tested against real coaching principles rather than hoping a black box got it right.

Accountable intelligence beats impressive intelligence when it’s your body on the line. We built the engine first, and everything else serves it.

Granite — a session in progress, with the reason for today and pain capture — Today’s set

Granite — the 12-week periodised plan, build phases and deloads laid out on a timeline — The 12-week arc

Fig. 05 · Granite · reasoning at every timescaleEvery session opens with why it exists today, inside a 12-week arc that builds and eases off on its own schedule — so you’re always working toward something, instead of guessing what to do next or grinding until you break.

On-device by decision

Granite runs entirely on your phone. No account, no cloud, no data leaving your hands — the privacy isn’t a policy you have to trust, it’s the architecture. Running locally was the harder path, and it made the product sharper: an engine that can’t lean on a server has to do its thinking right there, on your phone, the instant you need it.

That constraint is the craft. Spotting a plateau, checking a week’s volume against the evidence — the kind of analysis most apps would phone home for — happens instantly, with nothing leaving your hands.

Granite — plateau detection: Face Pull flagged flat for a few sessions, with a reason and a fix — It notices a plateau

Granite — weekly training volume per muscle group, checked against an evidence-based range — And checks the volume

Fig. 06 · Granite · reading the whole picture, on-deviceIt catches a plateau before you’d notice it yourself, and makes sure no muscle group is quietly under-trained — so a stall gets fixed in week one, not month three of wondering why you’ve stopped improving.

Art direction

Made before the app existed.

Concept film · not product footage

Movement

Goal

Equipment

Level

Action

Coach

Branding detail · Granite · the glyph setForty-five icons, drawn for this product rather than pulled from a system library: twelve for how a body moves — squat, hinge, push, pull — five for what you’re training toward, nine for the equipment you tell it you have, three for experience level, seven for the small actions inside a session, and the rest for how the coach explains itself. Every one is built from the same handful of shapes — a dot, a line, a ghost of where something used to be — so the system reads as one language, not a shelf of clip art.

The ledger · kept / cut

The product is the decisions we refused to skip.

+Kept

A rule-based engine you can trace
On-device — no account, no cloud
A weekly rewrite that explains itself

−Cut

An AI black box guessing your plan
Cloud sync and sign-in
Streaks, badges, a feed to scroll

One we killed

We almost shipped cloud sync in week three — it would have made onboarding one tap and the demo look cleaner. We killed it because the moment your training history touches our servers, “on-device and accountable” stops being an architecture and becomes a marketing line. The harder path was the product.

Scope. What is public here is the consumer app. The engine underneath it was built to serve more than one reader — and those surfaces stay off the site until they ship. The architecture is the asset; publishing how it decides is not.

StackSwift · SwiftUI · on-device

Timeline2026

ConstraintNo cloud. No account. No black box.

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