No prerequisites. If you've used Claude or ChatGPT and you're wondering what separates a one-off script from an agent that actually runs in production, this post is for you.

I wrote my first Python agent in April 2026. It did two things: read a PDF, send a Telegram message. It worked. Once.

The second time, the PDF was poorly scanned. The agent crashed. No trace. No notification. The patient never got their appointment.

That's the day I understood: an agent that works in demo is not an agent. An agent is what holds up when you're not around.

I wrote four words in the docstring of my next agent: Observability, Reliability, Security, Deployment. Since then, I haven't shipped a single agent to production without all four.…