Simon Willison’s Weblog

7th November 2025

You should write an agent (via) Thomas Ptacek on the Fly blog:

Agents are the most surprising programming experience I’ve had in my career. Not because I’m awed by the magnitude of their powers — I like them, but I don’t like-like them. It’s because of how easy it was to get one up on its legs, and how much I learned doing that.

I think he's right: hooking up a simple agentic loop that prompts an LLM and runs a tool for it any time it request one really is the new "hello world" of AI engineering.