Function cronToHuman

packages/agent-core/src/tools/cron/cron-expr.ts:350–408

(expr: ParsedCronExpression)

 * is fine and we don't try to be exhaustive.
 */
export function cronToHuman(expr: ParsedCronExpression): string {
  const allMin = isFullRange(expr.minutes, 0, 59);
  const allHour = isFullRange(expr.hours, 0, 23);
  const allDom = expr.daysOfMonthWildcard;
  const allMonth = isFullRange(expr.months, 1, 12);
  const allDow = expr.daysOfWeekWildcard;

  // every N minutes — common LLM pattern (`*/5 * * * *`).
  if (allHour && allDom && allMonth && allDow) {
    const step = detectStep(expr.minutes, 0, 59);
    if (step !== null && step > 1) return `every ${step} minutes`;
    if (allMin) return 'every minute';
    if (expr.minutes.size === 1) {
      const m = [...expr.minutes][0]!;
      return `at minute ${m} of every hour`;
    }
  }

  // every N hours.
  if (expr.minutes.size === 1 && allDom && allMonth && allDow) {
    const m = [...expr.minutes][0]!;
    const step = detectStep(expr.hours, 0, 23);
    if (step !== null && step > 1) {
      return `every ${step} hours at minute ${pad(m)}`;
    }
  }

  // at HH:MM every day, optional dow restriction.
  if (
    expr.minutes.size === 1 &&
    expr.hours.size === 1 &&
    allDom &&
    allMonth
  ) {
    const h = [...expr.hours][0]!;
    const m = [...expr.minutes][0]!;
    if (allDow) return `at ${pad(h)}:${pad(m)} every day`;
    const dowStr = formatDows(expr.daysOfWeek);
    if (dowStr !== null) return `at ${pad(h)}:${pad(m)} on ${dowStr}`;
  }

  // at HH:MM on day N of <month>.
  if (
    expr.minutes.size === 1 &&
    expr.hours.size === 1 &&
    expr.daysOfMonth.size === 1 &&
    !expr.daysOfMonthWildcard &&
    expr.months.size === 1 &&
    allDow
  ) {
    const h = [...expr.hours][0]!;
    const m = [...expr.minutes][0]!;
    const d = [...expr.daysOfMonth][0]!;
    const mo = [...expr.months][0]!;
    return `at ${pad(h)}:${pad(m)} on day ${d} of ${MONTH_NAMES[mo - 1]}`;
  }

  return expr.raw;