Claude Skill

## Your own training app,
built around your body

Answer some questions once. Claude writes you a programme, builds you a workout app you keep on your phone, plans your food if you want it, then coaches you session by session using what you actually lifted.

15 minutes to set up
Windows, Mac or Linux
Requires Claude
1

### Before you start

Two things you need in front of you.

Required
Do the setup on a computer. Everything in this guide happens on a Windows, Mac or Linux machine. Your phone comes in at the end, when the finished app is ready to add to your home screen.
Claude. Either Claude Code in a terminal, or the Claude desktop app. You need a paid Claude plan (Pro or above), or API credits; the free plan does not include Claude Code.
The unzipped folder you got with this guide. It contains a folder called `iron-os`.
Fitness guidance, not medical advice. If something hurts badly, is getting worse, involves numbness, or followed an accident, see a physiotherapist or doctor before starting any programme. The same goes for nutrition targets if you have a condition affected by diet. The skill will tell you this too.
2

### Install the skill

Copy one folder into place.

Required
What a skill is. A folder of instructions Claude reads. Nothing is installed on your computer, and deleting the folder removes it.

Pick your system. The steps below change with it.

1
Open a terminal in the unzipped folder

In File Explorer, open the unzipped folder, the one holding `iron-os` and this guide. Right click an empty space inside it and choose Open in Terminal. If that option is not there, click the address bar at the top, type `powershell` and press Enter.

2
Create the skills folder and copy it in

Paste these two lines into the terminal and press Enter.

PowerShell

    New-Item -ItemType Directory -Force "$env:USERPROFILE\.claude\skills" | Out-Null
    Copy-Item -Recurse -Force ".\iron-os" "$env:USERPROFILE\.claude\skills\"

1
Open a terminal in the unzipped folder

In Finder, find the unzipped folder, the one holding `iron-os` and this guide. Right click the folder, choose Services, then New Terminal at Folder. Or open Terminal from Applications and drag the folder onto its icon in the Dock.

2
Create the skills folder and copy it in

Paste these two lines into the terminal and press Enter.

Terminal

    mkdir -p ~/.claude/skills
    cp -R ./iron-os ~/.claude/skills/

3
Check it landed

You should see `SKILL.md`, `assets` and `references`.

Verify

    ls ~/.claude/skills/iron-os

Restart Claude afterwards. Skills are picked up when it starts, so close it and open it again before the next step. The folder is about 11 MB, almost all of it exercise artwork.
3

### Make a home for it

One folder you always start Claude from.

Required

Your profile, your plan and your app file all live in this folder, and Claude looks here first, so start Claude from here every time. The commands below create it, move the terminal into it and start Claude.

PowerShell

    New-Item -ItemType Directory -Force "$env:USERPROFILE\iron-os" | Out-Null
    Set-Location "$env:USERPROFILE\iron-os"
    claude

Terminal

    mkdir -p ~/iron-os
    cd ~/iron-os
    claude

Next week, and every week after. Open a terminal, run the last two lines again, and Claude picks up exactly where you left off. Start it somewhere else and it will not find your files.
Using the Claude desktop app instead of a terminal? Create the same `iron-os` folder, then in the app open the Code tab, choose that folder as the project, and type the same sentence. The skill is picked up from `~/.claude/skills` either way.
4

### Run it

One sentence starts everything.

Required

Type this to Claude:

Say this

    Set up my training app

Or `/iron-os` if you prefer slash commands.

The first thing it asks is which half you want. They are independent, and you are never pushed into the other one.

#### Training

The workout app and the programme. Nothing about food is ever mentioned.

#### Food

A weekly meal plan on its own. It skips every question about injuries, equipment and lifts.

#### Both

The full thing, with your food targets shown in the workout app.

You can add the other half later. Start with training, decide in week three you want the food side too, and just ask. Nothing needs redoing.
5

### The intake

Nine short sections. Roughly ten minutes.

Required
1
Answer the questions

Who you are, your goal, injuries, your week, your gym, your current lifts, how you train now, whether you want dieting and building phases, and what to call the app.

2
Be blunt about injuries

This is the section that changes your programme most. "My shoulder is a bit dodgy" is not enough to work with. Say what hurts, what brings it on, and how bad it is out of ten. Anything you rule out never appears in your app, not even as a swap option.

3
Approve the programme

You get the plan as a document first. Read it, argue with it, ask for exercises to be swapped. Nothing is built until you are happy with it.

"I don't know" is a good answer. Especially on lift weights. A sensible starting weight beats a number you made up, and the first fortnight finds the right load anyway.
6

### Your app

What you get, and where to keep it.

Automatic

Claude writes you a single file, something like `ben-iron-os.html`. Open it in any browser.

302 exercises Properly drawn, three frames each. Tap any picture to watch the movement play.
Swap anything Don't like an exercise? Swap it. Same muscle offered first, search for the rest. Your history follows the movement.
Rest timer Starts itself when you tick a set. Adjust it or skip it.
Technique cues Five per exercise, written for you, not copied from a textbook.
Weekly volume Sets per muscle over the last seven days, with targets that shift with your phase.
Records Beat a best and the app says so.
1
Put it on your phone

Three ways to do it, best first. Phones do not open a plain file the way a computer does, so the first one is the one that works properly.

#### A · Host it, free

Recommended. Make a new folder, put a copy of your app file in it and rename that copy `index.html` (keep the two icon files beside it). Go to app.netlify.com/drop, sign in with a free account, and drag the folder onto the page. It gives you a link. Open that link on your phone in Safari or Chrome, tap Share, then Add to Home Screen. It opens like any other app after that. When Claude rebuilds your app, drop the folder again on the same site and the link stays the same.

#### B · Send the file

Send the file to your phone over WhatsApp or AirDrop and open it there. It works for a look, but see the warning below before you rely on it.

#### C · Use the computer

Open the file in any browser on your laptop and keep it beside you while you train. Fine for a home gym.

About that link. It is private and unlisted: nobody finds it unless you give it to them. The only thing on the server is the app file itself. Nothing about you or your training is on it. Your history stays on the phone.
Option B on an iPhone. A file opened from Files shows as a preview. You cannot add it to the home screen from there, and your history may not survive between opens. Android is better but not guaranteed. Option A is strongly recommended.
2
Back it up occasionally

Menu, then Export backup. Your history lives on the device, so do this before changing phones.

Nothing leaves your device. There is no account and no cloud unless you switch sync on yourself in the menu.
7

### Your food

Only if you asked for it.

Optional

If you chose the food side, you get a second file: a week of meals with a shopping list, built around what you actually eat and how long you will actually spend cooking.

One question decides the whole shape of it.

#### Keep it simple

A plan built to hit your target. No counting, no weighing, no macros on screen. Eat what is on the plan and the numbers look after themselves.

#### Match my training

More carbohydrate on hard days, less on rest days, protein steady throughout. Every meal shows its numbers.

Most people should pick simple. Precise is worth it if you are chasing a peak or already enjoy tracking. Otherwise it turns food into a job for very little return.

You also get a supplements panel, and it is honest rather than promotional. It works out whether your food actually falls short of your protein target and tells you plainly when no shake is needed. Ask for next week's plan whenever you want one.

8

### Getting coached

The part that makes it worth doing.

Ongoing

After a session, tell Claude how it went. It reads your profile and your plan, asks how you slept and whether anything hurt, then tells you what to do next time. When the programme genuinely needs to change, it rebuilds your app file.

1
Copy the session from the app

Open the app menu and tap Copy session summary. It puts the whole session on the clipboard: the date, every set you logged and your check in scores.

2
Paste it to Claude

Type the line below, paste the summary after it, and send. Claude does the rest.

Say this

    Just finished day 1, here is the summary:

Keep the files together. `iron-os-profile.md` and `iron-os-plan.md` sit next to your app file. They are the memory. Start Claude in that folder and it knows exactly where you are.

### Quick reference

Say this | What happens
--- | ---
`Set up my training app` | Starts everything. Asks whether you want training, food, or both.
`/iron-os` | The same thing, as a slash command.
`Copy session summary` | In the app menu, not in Claude. Puts today's session on the clipboard, ready to paste into the chat.
`Here's how today went…` | Logs the session, gives a verdict, sets the next one.
`What am I doing today?` | Tells you the next session and the weights to use.
`My knee has started hurting` | Adds the constraint, swaps affected exercises, blocks them from the swap list, rebuilds the app.
`I'm starting a diet on Monday` | Switches phase, cuts volume to the maintenance dose, and moves your food targets.
`Make me next week's meal plan` | A fresh week of food against the same targets.
`Add the food side` | Adds meal planning to an existing training setup, or the reverse.
`Rebuild my app` | Regenerates the file after programme changes.
`Add cloud sync` | Optional, advanced. Claude points you at `references/cloud-sync.md`.