Function checkPromptUnicode

scripts/check-repo-hygiene.mjs:428–456

(file, content)

}

function checkPromptUnicode(file, content) {
  let line = 1;
  let column = 1;

  for (const char of content) {
    const codePoint = char.codePointAt(0);
    const classification = classifyPromptCodePoint(codePoint);

    if (classification) {
      addFailure({
        ruleId: "prompt/no-hidden-or-control-unicode",
        title: "Prompt files must not contain hidden Unicode controls",
        file,
        problem: `${file} contains disallowed ${classification} ${formatCodePoint(codePoint)} at ${line}:${column}. AI prompt files must not contain invisible Unicode, bidirectional overrides, or terminal control characters.`,
        why: "Hidden Unicode and terminal controls can conceal prompt-injection text or make review output misleading.",
        fix: "Remove the disallowed character and keep prompt text visible ASCII or ordinary visible Unicode only.",
      });
    }

    if (char === "\n") {
      line += 1;
      column = 1;
    } else if (char === "\r") {
      column = 1;
    } else {
      column += 1;
    }
  }
}

function classifyPromptCodePoint(codePoint) {
  if (isBidirectionalTextControl(codePoint)) {