AI-assisted rewriting has an awkward failure mode: the prose gets better while a small, important fact gets worse.
A date moves by three days. A pilot cohort shrinks. A link disappears. None of these changes necessarily makes the paragraph sound suspicious.
I built KeepFacts as a deliberately narrow preflight check for that problem. It compares a trusted source with a rewrite, summary, or translation and asks one question:
Were the exact facts that KeepFacts can recognize preserved?
It does not ask an LLM to judge another LLM. It does not search the web or decide whether a claim is true. The comparison is deterministic and runs locally in the browser.
