2023: prompt engineering.
2025: context engineering.
2026: loop engineering.
The label keeps changing. The skill underneath never did.
Karpathy, Boris Cherny, and Steinberger all moved the skill to loop engineering, and those names carry weight.
Each one renamed the same job. Prompt engineering meant writing the right sentence. Context engineering meant feeding the model the right information. Loop engineering means wrapping an agent in a program that runs until a test passes.
What changes across all three is where you make the call, not whether you have to. You still decide what good looks like before the model runs.
Nobody mentions the bill. One loop can burn $50 to $100 in credits on a single task. The people posting $20,000 daily token runs aren't paying out of pocket.
A loop pays the model to supply judgment it doesn't reliably have. You supply that for free. Spend the thinking before the tokens, send cheap work to cheap models, cache what repeats, stay in the loop yourself.
The name on the skill will change again next year. The skill won't.
Alex Prompter (@alex_prompter)
— https://nitter.net/alex_prompter/status/2067653263453806800#m