# Cairn — Become.

> A coach that has already read your whole day, and has one honest thing to say.

Cairn 2.0 · self-hosted · open source · MIT · https://cairn.fit/

- Source: https://github.com/zilet/cairn
- Try the demo in your browser: https://codespaces.new/zilet/cairn (a real Cairn on fictional data in a GitHub Codespace; nothing touches your machine)
- Walkthrough video: https://cairn.fit/trailer.mp4 (Cairn 2.0 on fictional demo data, 0:58; also on YouTube: https://www.youtube.com/watch?v=O5sEmIWaR8M)
- [BECOME, the film](https://www.youtube.com/watch?v=BkMJtestJzo): a short film about Cairn, 1:16

Cairn reads your lifting, running, food, sleep, labs and life as *one picture*. It opens to a calm read of today: rest, easy or train, with the reasons shown. A team of specialists works quietly behind it, makes the small calls, and gives you a one-tap Undo for each one.

It runs on your own hardware, keeps everything in a SQLite file you own, and never scores you or nags you.

## What it does

### Today: It reads your day.

Today opens on an answer, not a dashboard. Rest, easy or train, in one sentence, with the evidence a tap away: last night's sleep, your HRV against *your own* band, the load you carried this week, the knee you mentioned on Tuesday.

A suggestion, never a gate. A missing night says nothing, never "bad".

### The team: The team decides. You can Undo.

Strength, endurance, nutrition, physio and an informational health seat each watch their part of you. When the evidence is clear, a bounded change lands on its own, with its why in plain words and one tap to put it back. Anything clinical, irreversible or goal-changing still asks first.

### Labs: Your blood's been talking.

A flagged marker doesn't sit in a PDF. It travels into your meals, your training and your watch, each with its why and a citation. Before a visit, the doctor packet builds itself, in clinical order.

Informational, never medical advice.

### Fuel: Measured, not punished.

Type a meal the way you'd say it, or snap the plate, and it comes back as a card you can correct. Expenditure comes from your real weight trend. A thin logging week lowers confidence; it never blames you.

### Horizon: A race build sized to you.

Name a half marathon and Horizon draws the road to it from the weeks you actually ran. The best week you've already run safely sets the floor; the peak aims just past it. Strength keeps progressing all the way to race week.

### You: Six stones. One picture.

Strength, endurance, fuel, recovery, body and heart, each with one word for where it stands right now. Tap a stone to see what it leans on: a ferritin still catching up quietly holds the running back.

Words and your own baseline, never a 0–100.

## The rules don't change.

- **No scores.** No grades, no 0–100, no metric walls.
- **No streaks.** Nothing to keep alive, nothing to lose.
- **Nothing pushed.** Insights wait in the app until you want them.
- **A suggestion, never a gate.** Every read is advice. You drive.
- **Clinical asks first.** Anything medical waits for your yes.
- **Yours.** Your hardware, one SQLite file, MIT licensed.

## Run it tonight.

One container, amd64 or arm64. A Raspberry Pi is plenty.

```sh
docker run -d --name cairn -p 127.0.0.1:8787:8787 \
  -v cairn-data:/data -v cairn-home:/home/app \
  -v cairn-tools:/home/app/.cairn-tools \
  --restart unless-stopped ghcr.io/zilet/cairn:latest
```

Then open http://localhost:8787. Garmin, Apple Health, lab PDFs and the coaching agents (Claude Code, Codex and others) are set up from inside the app. Quickstart: https://github.com/zilet/cairn/blob/main/docs/QUICKSTART.md

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Cairn is open source under the MIT license: https://github.com/zilet/cairn

Every screen shown is the real app on fictional demo data. Cairn is informational and is not medical advice.