Fitness OS

I let Claude run my training.

Every year I seem to have less time for fitness, not more. The 20-minute workout trend actually fit my life, so I found a program I liked, bought it, and then did the thing that made it stick: I handed it to an agent.

Claude is the coach. It built my training blocks from the program's documentation and adjusts them week to week as I progress, add equipment, or tell it how a session felt. My goals now are longevity and balance, and a sustainable 20 minutes every day beats a heroic hour I will skip.

The daily loop

1. In the morning I ask Claude for my workout.
2. It drafts the session from the tracker: movements, targets, what to beat from last week.
3. I write it on a whiteboard and take it to the backyard.
4. I photograph the whiteboard and Claude extracts and logs the numbers.
5. I tell it how it felt, and it adjusts.

Everything is plain markdown in a git repo. Versioned, diffable, readable on a phone, and it doubles as an Obsidian vault. A photo of a whiteboard is the whole logging interface.

Why an agent instead of a fitness app

• It reads my program. Any PDF I buy becomes the coach's manual. No waiting for an app to support it.
• It remembers what an app cannot hold. "That bell is too heavy for pressing." "Grip gave out before my back did." "Only three rounds, ran out of time." Notes like that change next week's plan.
• The data is mine. Markdown tables in my own repo, forever. No subscription, no export button, no dead app taking my history with it.
• Zero friction. The whole thing runs from a whiteboard and a phone camera.

The method is not mine

The program is "How to Get Jacked in Under 20 Minutes a Day" by DailyRepsGuy (Skye Mack): one 20-minute AMRAP circuit a day, phase-based movement progressions, sustainability over maximal volume. It is excellent and inexpensive, and this whole setup exists because of it. Go buy it.

His guide is paid content and is not in the repo, which is the point of the design. You buy a program, drop the PDF into a gitignored folder, and the agent reads it as the source of truth for movements and progression. What I built is the system around a program, not a program.

Take it

The template is public: github.com/prounds-4/20-minute-fitness. Clone it into a private repo, since the log is your own data, add your program, edit the agent brief, and open the folder in Claude Code.

The same idea as Personal OS. Design the system once, then let the agent maintain it. The rest of what I build is at Projects.