static F1<S> botEval_strictSafetyCheck() {
  ret func(S code) -> S {
    S safety = joinWithComma(getCodeFragmentSafety(code));
    if (eq(safety, 'safe)) ret "";
    S s = "Sorry. Safety level is " + safety;
    Set<S> unknown = codeAnalysis_getUnknownIdentifiers(code);
    if (nempty(unknown)) s += ". Unknown identifiers: " + joinWithComma(unknown);
    ret s;
  };
}