Function toolFenceRanges

lib/redact-engine.ts:188–209

* Returns a sorted list of [start, end) offset ranges (in normalized text) that * sit inside a tool-attributed fenced code block. Credential findings inside * these ranges degrade to WARN (unless the doc-example heuristic says the span * is live-format and must still block).

(normalized: string)

 * is live-format and must still block).
 */
function toolFenceRanges(normalized: string): Array<[number, number]> {
  const ranges: Array<[number, number]> = [];
  const lines = normalized.split("\n");
  let offset = 0;
  let inFence = false;
  let fenceStart = 0;
  for (const ln of lines) {
    const isFenceMarker = ln.startsWith("```");
    if (isFenceMarker) {
      if (!inFence && TOOL_FENCE_INFO.test(ln)) {
        inFence = true;
        fenceStart = offset + ln.length + 1; // content starts after this line
      } else if (inFence) {
        ranges.push([fenceStart, offset]); // up to start of closing fence
        inFence = false;
      }
    }
    offset += ln.length + 1; // +1 for the \n
  }
  if (inFence) ranges.push([fenceStart, normalized.length]); // unterminated → still degrade its own body
  return ranges;
}

function inRanges(offset: number, ranges: Array<[number, number]>): boolean {
  for (const [s, e] of ranges) if (offset >= s && offset < e) return true;