One prompt line nearly tripled an agent's simulation success rate

A controlled study cut an AI agent's stale-data errors by two-thirds by adding one line to its prompt. Bounded task success across 120 trial slots per arm went from 35 to 95 when agents were told to re-run their simulator after real edits.

Five Qwen models ran eight process-engineering tasks against a DWSIM simulator. A new arXiv study tested this by having guided agents request a fresh simulation after any substantive change, while unguided agents got no instruction.

Guided agents re-verified in 94 of 120 slots, versus 32 of 120 for the unguided group. Cadence violations, cases where an agent kept editing without re-checking, fell to 26, down from 87.

One of the five models ignored the instruction entirely and never succeeded on any task, guided or not. The paper doesn't say why it resisted the cadence instruction while the other four followed it.

Anything that hands an LLM a stateful tool, a test runner, a simulator, a linter, a build, hits this same failure mode. Try a plain-language re-verify rule before adding retry wrappers or output validators. The retry logic still has a job. It's just not the first job.