paperclipai/paperclip · error · Error

Cron expression must have exactly 5 fields, got ${tokens.len

Error message

Cron expression must have exactly 5 fields, got ${tokens.length}: "${trimmed}"

What it means

Shape guard in parseCron: after whitespace-splitting, the expression does not have exactly 5 tokens (minute hour dom month dow). The message reports the actual token count and the full trimmed expression so the fix is obvious.

Source

Thrown at server/src/services/cron.ts:212

 * @returns Parsed cron with sorted valid values for each field.
 * @throws {Error} on invalid syntax.
 *
 * @example
 * ```ts
 * const parsed = parseCron("0 * * * *"); // every hour at minute 0
 * // parsed.minutes === [0]
 * // parsed.hours === [0,1,2,...,23]
 * ```
 */
export function parseCron(expression: string): ParsedCron {
  const trimmed = expression.trim();
  if (!trimmed) {
    throw new Error("Cron expression must not be empty");
  }

  const tokens = trimmed.split(/\s+/);
  if (tokens.length !== 5) {
    throw new Error(
      `Cron expression must have exactly 5 fields, got ${tokens.length}: "${trimmed}"`,
    );
  }

  return {
    minutes: parseField(tokens[0]!, FIELD_SPECS[0]!),
    hours: parseField(tokens[1]!, FIELD_SPECS[1]!),
    daysOfMonth: parseField(tokens[2]!, FIELD_SPECS[2]!),
    months: parseField(tokens[3]!, FIELD_SPECS[3]!),
    daysOfWeek: parseField(tokens[4]!, FIELD_SPECS[4]!),
  };
}

/**
 * Validate a cron expression string. Returns `null` if valid, or an error
 * message string if invalid.
 *
 * @param expression — A cron expression string to validate.

View on GitHub (pinned to 120ae5428f)

Solutions

1. Use exactly 5 fields (minute hour day-of-month month day-of-week) in the cron expression.

When it happens

Trigger: Thrown at server/src/services/cron.ts:212 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of paperclipai/paperclip@120ae5428f (2026-08-18). Data as JSON: /api/errors/6286211eb334fd31. Report an issue: GitHub.