Knowing When to Stop: The Art of Making a Loop Converge | Andreessen Horowitz
Infra<br>Knowing When to Stop: The Art of Making a Loop Converge
Yoko Li
Posted<br>August 6, 2026
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Knowing When to Stop: The Art of Making a Loop Converge<br>Table of Contents
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How can an AI model know when its work is done?
Well, how does a human know when our work is done.
A programmer waits for the tests to turn green or waits for PR review from their team. A designer adjusts a composition, steps away, returns, and decides the remaining imperfections no longer matter. A writer submits a draft because the deadline has arrived or because an editor accepts it, not because the prose has reached some objectively final state.
“Done” is rarely a property of the work itself. It is a judgment produced by the system around the work. Humans do not possess a universal detector for “done”. We rely on a patchwork of signals like tests, specifications, precedent, approval, deadlines, risk, and finding that point of diminishing returns. In each case, completion comes from outside the work itself.
The Model that Could Continue Forever
An AI model can almost always produce another answer.
It can revise the paragraph again. It can try another implementation. It can generate another image with more detail, different lighting, and a stronger composition. It does not become tired of the work. It does not notice, unless we give it some way to notice, that the last three revisions made the result different but not necessarily better.
This is part of what makes the recent idea of loop engineering so compelling. Instead of a human prompting a model, inspecting the result, describing what went wrong, and prompting it again, we can ask the system to perform the whole cycle itself. The person no longer has to sit inside every turn. The agent discovers the work, gives it to the model, checks the result, and decides what should happen next.
Peter Steinberger 咽<br>@steipete
Here’s your monthly reminder that you shouldn’t be prompting coding agents anymore.
You should be designing loops that prompt your agents.
6:58 PM · Jun 7, 2026
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However, the nuance when writing a loop is that the loop is only as good as the verifier at each step . Even before we started talking about loop engineering,...