Prompt vs Loop: when to iterate
2026-08-01 · 4 min read
A practical comparison of single-shot prompting and iterative agent loops, with the exact signals that tell you to upgrade.
The difference in one line
A prompt asks. A loop insists. Prompting optimises the request; looping optimises the result.
Upgrade signals
- You keep pasting the output back in with 'now fix X'
- Quality varies run to run
- The task has an objective pass/fail test
- Cost of a wrong answer is higher than cost of another iteration