Loop Engineering from First Principles — Kyle Mistele, HumanLayer
Source
AI Engineer
Author
AI Engineer
Date
Terms in this piece · Glossary
AI agent — An AI system that doesn't just answer once but works toward a goal in a loop — taking actions, reading the results, and deciding what to do next.
Why it matters
A concrete, testable structure for long-running AI agentAn AI system that doesn't just answer once but works toward a goal in a loop — taking actions, reading the results, and deciding what to do next.Full definition → work that keeps every iteration reviewable, which is the difference between an agent you can leave running and one you cannot.
Key quotes
“we're still building 40,000line PRs that just nobody wants to read, right?”
Kyle Mistele
“Control loops change a system incrementally instead of just trying to get straight to the end state immediately all at once and risk blowing everything up, right?”
Kyle Mistele
“I don't think you should ever send an agent to do deterministic code's job, but you certainly can.”
Kyle Mistele
“bad code is much more expensive in the age of agents than it it has ever been at any point in the past”
Kyle Mistele
“idiomatic handwritten examples for the agent to follow because they're just pattern replicators and otherwise you're getting what's in the docks or what the agent knows from the internet”
