What is Loop Engineering?
2026-08-01 · 6 min read
Loop Engineering turns a single prompt into a self-improving agent that plans, executes, validates, improves, and retries until it meets a defined success condition.
One intelligent worker
A loop is a prompt with a feedback mechanism. Instead of accepting the first answer, the agent evaluates its own output against explicit criteria and iterates until the criteria are met or a stop condition fires.
The five phases
Every well-formed loop cycles through the same phases.
- Plan — decompose the goal into steps
- Execute — perform the current step
- Validate — score the output against criteria
- Improve — rewrite based on the critique
- Retry — repeat until success or stop condition
Stop conditions matter more than the prompt
The most common failure in loop design is an unbounded loop: no iteration cap, no cost budget, no acceptance test. Define the exit before you define the work.