Building an AI Agent from Scratch, Part 1: What Even Is an Agent Harness?
You’ve seen the demos. AI agents booking flights, writing code, querying databases, probably filing your taxes while whispering sycophantic flattery. Very impressive. Very “the future is here.” Here’s the simple secret nobody mentions in the keynote: LLMs can only produce text. That’s it. They can’t run code. They can’t check the time. They can’t read a file. They are the world’s most confident interns — full of opinions, zero ability to actually do anything. All they do is predict the next token and hope you’re impressed. ...