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Esther Studer
Esther Studer

Posted on • Originally published at mypettherapist.com

I built an AI that diagnoses your pet's weird behavior — here's what I learned

I built an AI that diagnoses your pet's weird behavior

Six months ago I built mypettherapist.com as a side project. The idea: you describe your pet's quirky behavior, and Dr. Pawsworth (our AI vet) gives it an absurd but weirdly accurate medical diagnosis.

What it does

You type: "My cat stares at the wall for 20 minutes and then runs through the apartment at 3am"

Dr. Pawsworth responds: "Diagnosis: Nocturnal Hyperactivity Compulsion Disorder (NHCD). Severity: CRITICAL. Treatment: Accept the chaos. Schedule wall consultations. This is now your life."

The tech stack

  • Frontend: WordPress (I know, I know)
  • Backend: FastAPI (Python) running on port 8001
  • AI: Claude (Anthropic) with a carefully crafted system prompt that makes it act like a slightly unhinged veterinarian
  • Database: PostgreSQL for session management

What surprised me

The engagement rate is insane. People spend an average of 4+ minutes on the site — much higher than typical tool sites. The diagnosis results get shared. People tag their friends.

The secret: the AI takes the diagnosis completely seriously. It uses real medical terminology. It provides treatment plans. The absurdity works because the tone is dead straight.

The prompt engineering

The key was giving Dr. Pawsworth a clear personality brief:

  • Always diagnose, never dismiss
  • Use real-sounding medical terms
  • Treatment plans must be simultaneously useless and oddly wise
  • "(Not a real doctor)" appears exactly once per session

Try it

Free at mypettherapist.com — your pet deserves a diagnosis.

What's the weirdest thing your pet does? Drop it in the comments and I'll run it through Dr. Pawsworth 👇


I'm also working on a sister project — jobwechsel-ki.ch — AI-generated CVs and cover letters for the DACH job market. Different vibe, same principle: use AI to do something humans find tedious.

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