Fatcamp

An agent that builds your training session from three things: what equipment you have, what you want to hit, and how much you've got in the tank. Then it shows you how to do every movement, in 3D.

No dependencies, no build step, no bundler. Install it to your home screen and it trains you in a basement with no signal. Signing in is optional and only ever adds a leaderboard — the generator, the 3D body and your whole log work offline exactly as before.

What it does

Just say it. The box at the top takes the request the way you'd say it out loud — "push day at home, six movements, go hard", "45 minutes of legs and a steady state run", "killer leg day with back squats and RDLs". It reads the location, the muscle groups, the movement count, the effort, the conditioning and any lifts you name by name, fills in the whole Workload panel, and forges the session in one press. Each ask is a complete request rather than an edit of the last one, so yesterday's bench press cannot turn up in today's leg day. Anything it doesn't recognise it leaves alone. Behind the box a shape turns slowly through the gym and back again — dumbbell, kettlebell, barbell, medicine ball, a flexing arm, a bicycle, a treadmill, a bench, a rope, resistance bands and a forge hammer.

Presets, if you don't want to think. Four of them — Easy Day, Medium Day, Killer, Cardio. One tap fills in every criterion below it. Change whatever you like afterwards, or just forge it. The card marks the effort in bolts — one, two, three — in the plate colour that codes it everywhere else; Cardio gets a runner on a treadmill instead.

Home, public gym, or nothing at all. Home uses a kit you define once — the generator will never prescribe a lift you can't load. Public gym opens up racks, cables, machines and conditioning gear. Body Weight strips it to you and the floor: a hotel room, a park, ten minutes between things. Twenty-seven movements need no equipment whatsoever, covering fourteen of the twenty-three muscle regions. Lats and biceps are not among them — there is no honest way to load a pull without something to hang from, so the mode says so on the panel rather than inventing something.

Coverage-first generation. You pick the compound lifts you want and the muscle groups you care about; the generator fills the remaining slots by greedily maximising new muscle coverage, keeping movement patterns balanced and ordering the sheet the way you should actually train it — compounds first, isolation later, core at the end. Every movement tells you why it earned its slot, and the session shows you which muscle groups it missed.

A shaded 3D body for every movement. Not a stick figure and not a video — a procedural anatomical mesh whose every surface quad knows which muscle it belongs to. Drag to orbit, snap to side / three-quarter / front, or set it spinning. Equipment and surfaces are drawn in 3D too: floor, bench, rack, bars with plates on both ends, bands anchored to the ground.

The same body is the heat map. Because each quad carries a muscle id, colouring by activation turns the figure itself into the chart — rotate it to see exactly what today's session lands on, front, back or side. No more guessing from a flat silhouette.

It notices what you skip. The generator keeps a rolling read of the last fortnight and builds up a debt for muscles that keep getting missed, then pays it down in later sessions and tells you when it does.

Personal bests. Log a lift's load and reps from the session sheet or from your profile, for the big lifts or any movement you name. Entries are ranked by estimated 1RM (Epley) so a heavy triple and a set of ten can be compared, and each lift gets its own chart over time — one lift at a time, because a deadlift and a curl have no business sharing a y-axis.

Failure mode. Switch it on for the session and isolation and accessory work drops its rep target — you go until the set stops. Compounds keep their numbers on purpose. Per movement you can toggle it either way; when it's on the figure runs the rep faster, trails behind itself, and the frame glows. Those sets are worth more.

Points, claimed as you go. Finish a movement's sets and claim its points right there — the balance moves while you're still in the gym. Whatever you don't claim is settled when you bank the session, so the total is the same either way and nothing pays twice.

Streaks you can see. The log keeps a calendar over a week, a month or the last twelve months, each day coloured by how hard that session was. Ranks go from Empty Bar to Cast Iron. Training at least every other day keeps a streak alive, and every seventh day banks a rest-day pass that covers one longer gap.

Build the week. Pick a split — Push/Pull/Legs, Upper/Lower, Full Body ×3, a body-part split, or set it day by day — and every session in it is generated at once. The split is what gets saved; the movements are re-rolled each time it's built, so the same routine keeps landing on different work. Planned days show up on the streak calendar ahead of time, so opening the app tells you what today is.

Standings. Points rank you rather than buy things. Your total, your week, your best session and your streak multiplier, plus a breakdown of exactly where points come from and which lever is worth the most right now. Sign in and you join local, country and global leaderboards.

Accounts and leaderboards

Optional, and additive. Signed out, the app is exactly what it was.

Sign-in lives in the profile, behind the avatar at the top of the page. There is an emailed six-digit code, the link in that same email, or a password — whichever suits. The same email carries both a six-digit code and a link, and the app accepts either — type the code, or tap the link and it returns you signed in (tokens are read from the URL fragment and immediately scrubbed out of history).

Supabase settings this depends on, under Authentication:

• URL Configuration → add every origin you serve from to Redirect URLs (http://localhost:8080/**, and your Pages URL). The link in the email comes back to whichever origin asked for it, and an origin that is not on this list is refused.
• Email Templates → Magic Link → include {{ .Token }} if you want the code to appear. The stock template only has the link.
• The built-in mailer is rate limited to a couple of sends an hour, which is easy to trip while testing. Authentication → Rate Limits shows the current caps; wiring your own SMTP under Project Settings → Auth → SMTP removes the constraint.

What leaves your device: a handle, a coarse region, and per-session point totals. What never does: your movements, loads, PRs, gym photo, or email. That split is enforced by Postgres row-level security, not by the client:

Table	Who can read it
lifters	only you
sessions	only you
standings	any signed-in user — handle, region and totals only

standings has no client write policy at all. It is maintained by a trigger that recomputes totals from sessions, so nobody can post a number they did not earn. The publishable key in index.html is meant to be public; these policies are the security boundary.

Setting it up

1. Paste supabase/schema.sql into the Supabase SQL editor and run it once.
2. Run supabase/verify.sh — it uses only the public key and asserts that the tables exist and that an anonymous caller can read and write nothing.
3. Open the app, go to Standings, and sign in.

Sync is best-effort: it runs after you bank a session and on load, never blocks the UI, and failures degrade to a quiet "Offline" note.

Install it on your phone

Serve the folder over HTTPS — GitHub Pages is the easy way (Settings → Pages → deploy from main, root) — then open the URL on your phone:

• iOS: Share → Add to Home Screen
• Android: the Install app prompt, or ⋮ → Install app

It installs as a standalone app with its own icon, no browser chrome, and a service worker that precaches everything. After the first load it never needs the network again.

To run it locally instead:

python3 -m http.server 8000

Opening index.html straight off disk works too, but service workers need http:// or https://, so you don't get offline install that way.

When you edit index.html, bump CACHE in sw.js. Installed copies are served cache-first and will otherwise keep showing the old version for a load.

Profiles

Progress belongs to a profile, and profiles live on the device. There is no server behind this app — that is what lets it run with no signal — so it can't offer a login that syncs by itself. Moving a profile to another device is an explicit, one-time act:

• Transfer code — a FATCAMP-… string you copy and paste into the app on the other device. Carries progress, streak, history and kit; not the gym photo.
• Backup file — a .json you can keep. Carries everything.

On import you choose to merge into the current profile (keeps the best of both, de-duplicates sessions) or add it as a separate one. Multiple profiles on one device work fine — useful if someone else lifts in the same room.

The home gym editor

Three ways to tell it what you own, all in the same sheet:

1. Tap the chips for anything in the library.
2. Type or paste a list. It understands commas, bullets, numbered lists and prose, plus the names people actually use — "power cage", "dumbells", "concept 2", "peloton", "hex bar", "parallettes". Anything it doesn't recognise is kept on your list rather than dropped.
3. Keep a photo of your gym as a reference to tick things off against.

On the photo: the app runs entirely on your device with no network, so it cannot analyse the image itself. What it does instead is give you a prepared prompt — hand the photo and the prompt to Claude, then paste the reply into the text box, which parses it. Fully automatic detection would need either a backend or an API key living in the browser; see Where this is going.

How it's built

index.html is the whole program. manifest.json, sw.js and icons/ exist only to make it installable.

Part	What it does
M	23 muscle regions
LIMBS / MUSCLE_AT	The body mesh: lofted tubes with radius profiles, and the rule that decides which muscle owns a surface point from its position along the bone and angle around it
buildMesh() / skinMesh()	Mesh topology is built once and shared by every rig; each frame only skins vertices and projects each one once, then paints faces back-to-front batching runs of like colour. ~6ms a frame, so it holds 60fps
muscleDebt()	Rolling read of what recent sessions neglected, fed back into generation
ARCH	49 movement archetypes — two authored poses each, plus the equipment to draw
solve()	Re-solves every frame against one canonical skeleton, so joint angles come from the pose and limb lengths never do
pose3()	Extrudes a solved 2D pose into 3D — sagittal archetypes gain left/right depth, frontal ones mirror in place
makeRig()	Canvas renderer: orbit camera, perspective projection, painter's-algorithm depth sort, depth-shaded capsule bones
X	The exercise library — muscles worked, equipment needed, movement pattern, coaching cue
generate()	The session builder: seeded compounds, greedy coverage fill, pattern balance, prescription. On a focused day only movements that mostly train the focus are eligible, so a chest day stays a chest day
parseEquipment()	Free-text and pasted-list equipment matching
movePoints() / scoreSession()	Per-movement claims and the session settlement that nets them off
epley() / prChart()	Personal bests, estimated 1RM, and the per-lift chart
bumpStreak() / trainingDays()	Streak rules, rest-day passes, and the calendar behind them
profile vault	Multiple profiles, v1→v2 migration, transfer codes, backup files

Exercises reference archetypes rather than owning poses, so adding a lift is a few lines in X — and the implement drawn in the figure's hands comes from the exercise's equipment, not the archetype, which is why a bodyweight calf raise holds nothing and a loaded one holds dumbbells.

Adding an exercise

{id:"zercher", n:"Zercher Squat", arch:"frontsquat", eq:["barbell","rack"],
 cls:"comp", pat:"squat", big:1,
 pri:["quads","glutes"], sec:["abs","upperback"],
 cue:"Bar in the crooks of your elbows. Brutal, and it will teach you to stay upright."}

cls picks the set-and-rep scheme (comp / acc / iso / core / cardio), pat keeps the session from stacking three horizontal presses in a row, and big:1 puts it in the compound picker.

Getting it on your phone, and into the store

DEPLOY.md covers both: turning on GitHub Pages and adding the app to your iPhone home screen today, and the Apple Developer / Capacitor / TestFlight path for a native release later. site/ is the marketing page — it links straight to the app, so it doubles as the front door on a laptop.

Design

The layout and typography follow the SkiLens Framer template: wide geometric display type set uppercase with tight negative tracking, corner-bracket eyebrow labels, 80px pill buttons with a circular accent badge, cards with one corner blown out to 48px and layered soft shadows. The top of the page is a single question over a frosted, translucent pane — Apple's liquid glass, more or less — with a slowly morphing form glowing behind it, in the manner of dough.do. That form is a rig of eight slots, each a lathe with its own place and tilt and a cross-section that can be squared off; a shape fills in the slots it needs and leaves the rest empty. The slot count never changes, so turning a bicycle into a bench is still a lerp, and a slot the next shape does not use borrows its partner's position so parts grow where they belong instead of flying out of the middle. A handwritten face appears once or twice as an aside, as it does in the template.

The forge button is the mark itself: a lightning bolt crossing a knurled dumbbell on a hot disc, with no chrome around it. It sits in the ask box, in the Workload panel next to the words Forge the session, and — once both have scrolled away — floating in the corner, so the session is always one press away. Hovering the Workload bar runs a row of chevrons across its empty middle, lighting in sequence toward the mark; the floating one carries a single chevron that breathes while it is up.

The palette stays the IWF competition plate colours, used as an actual coding system rather than decoration — red 25 kg for Killer, blue 20 kg for Cardio, yellow 15 kg for Medium, green 10 kg for Easy. The weights themselves are not printed on the cards; the colour is the code. Red carries the brand because that is what the mark is built from; the template's acid lime would have fought it. Every number is set in a monospace face so sets, reps, points and timers stay in tabular columns. Both light and dark themes are first-class; the toggle overrides your system preference.

The mark

A hexagon frame with circuit traces and a flexed arm, drawn as vector so it holds from a 16px favicon to a 512px store icon. logoMark(size) renders it inline and drops the hairline detail below 40px; the same paths generate icons/ and the favicon, so there is one source for the identity.

Plans

The first month is $5 with everything in Max unlocked, counted from the first time the app is opened. After that:

	Pro — $10/mo	Max — $17/mo
Sessions per week	unlimited	unlimited
Build-the-week training days	4	7
Saved splits	1	unlimited
Movements per session	10	20
3D rig, heat map, PRs, streaks, rewards	yes	yes
Failure mode	—	yes
Surprise Me	—	yes
Adaptive catch-up targeting	—	yes
Profiles on one device	1	unlimited

Per session, at the training days each plan allows: the first month is 16¢, Pro 58¢ across 17 sessions, Max 56¢ across 30. Max is the cheapest of the three per session because it buys nearly twice the days for $7 more.

Sessions are deliberately unlimited on both tiers. Metering how often somebody trains is the one limit that would make the app worse at its job; the paid line is drawn at depth and automation instead.

Billing is wired through StoreKit 2 on iOS: subscriptions are purchased through Apple, and entitlement is proved server-side — the app sends the App Store's own signed transaction (JWS) to a Supabase edge function that verifies it against Apple's certificate chain before unlocking metered features. Apple's App Store Server Notifications feed a subscriptions ledger the same way. In the plain web build there is still no payment code: choosing a plan applies its limits so each tier can be lived with, enforced client-side only.

Where this is going

1. Store builds. Capacitor or Tauri will wrap this for the App Store or Play Store with very little change, since there's no server to move.
2. Photo analysis without a courier. Two honest routes: a small backend that holds the API key and does the vision call, or an opt-in setting where you paste your own Anthropic key. The second keeps the zero-backend property but puts a real credential in browser storage, which is a genuine tradeoff rather than a free win.
3. Split the source. Once it's a store app, break index.html into modules and move the exercise library into JSON so it can be edited without touching code.

Not medical advice

Warm up. Leave a rep in the tank when the prescription says so. If something hurts in a way that isn't muscular, stop and talk to someone qualified.

Reading the funnel

npm run funnel prints the live metrics CSV — subscribers, revenue, installs, forges, banks, shares, and opens by ?p= source — as a table. The key is deliberately not in this repository: put it in ~/.config/fatcamp/metrics.key or export FATCAMP_METRICS_KEY.