---
id: CRON-2
family: RT-CRON
level: extended
profiles: [runtime]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/rt-cron/cron-2
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# CRON-2 — Every reason a schedule has no next run carries a stable code

*RT-CRON (Part II) · level: extended · profiles: runtime · added in 1.0*

The report of a trigger's next run is the only view of a schedule an operator has. A report that cannot distinguish "fine, nothing due" from "will never fire" is the diagnostic being absent exactly when it is needed.

## The rule

> **Normative.** This is the rule.
>
> 1. An absent next run, reported on its own, means only that nothing is currently due, the answer a perfectly healthy schedule gives between fires.
>
> 2. Every other reason a schedule yields no next run must be reported with a stable code: `no_expression` where the expression is cleared, `invalid_expression` where it is malformed, or well-formed but unsatisfiable.
>
> 3. Severity must not be flattened: an unusable timezone does not stop a trigger, since the implementation substitutes UTC, so such a schedule still reports a real next run alongside the code `invalid_timezone`; an expression problem, being the more consequential of the two, takes its place.
>
> 4. A broken stored schedule is not a broken request: the report is answered with 200 and carries the diagnosis.

## Related rules

- Names: CRON-1
- Referenced by: CRON-1

---

Rule identifiers are permanent and are never renumbered. This specification carries
no implementation status: each implementation publishes its own standing against
these rules. Licensed CC BY 4.0.