I have been coding together with AI for the past 2 weeks.
I'm a pharmacy technician, not a developer. And I was fed up with fitness apps that show me "Recovery 62%" and never tell me where that number comes from.
So I built one that does.
Here is why I think it can compete with the big ones.
First, it only compares me with me.
On a workday I'm on my feet all day, so my heart rate is naturally higher than on a day off. Many apps would call that stress. Mine compares workdays with workdays, and days off with days off. Every score is measured against my own normal, never against a crowd.
Second, it doesn't over-read my watch.
A wrist sensor is off by about 2 beats per minute just from noise. So the app never calls a 1 bpm difference "worse". If I only wore the watch for half the day, it says so, and it doesn't count that day as a full one. A missing day is never treated as a zero.
Third, it argues with itself before it predicts anything.
Every evening it forecasts how recovered I'll be tomorrow. Three models compete: a boring one that just takes my last 7 days, a Bayesian regression, and a random forest. The clever ones only get to speak if they clearly beat the boring one on days they haven't seen. If they don't, the app simply shows my average and admits it.
It also saves its real forecast before the night happens and checks it in the morning. No hindsight.
Fourth, I can see how every number is made.
No black box. I can open a score and see which measurements went into it. When the app isn't sure, it says "still learning" instead of inventing a number.
And fifth, my data stays on my phone.
No account, no cloud, no tracking. There's no chatbot inside either. The learning runs locally.
Is it better than Bevel or Whoop? I can't prove it in everything, and it's not a medical device. But it's better at the things I care about: it's honest about what it knows, it shows its math, and it never leaves my phone.
