---
id: INT-5
family: RT-INT
level: core
profiles: [runtime]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/rt-int/int-5
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# INT-5 — Cancel and pause signals are observed between job iterations

*RT-INT (Part II) · level: core · profiles: runtime · added in 1.0*

A signal never interrupts a job mid-flight. It is observed at the boundary between iterations, which is why a cancelled run has no half-executed node.

## The rule

> **Normative.** This is the rule.
>
> 1. An engine polls for a pending signal between job iterations; the in-flight job always finishes first, and the absence of a signal continues the loop.
>
> 2. A cancel signal marks the run cancelled, stamps its execution time, and announces the outcome twice: a cancellation event and a run-completed announcement carrying the cancelled status, so that cancellation is announced like any other terminal outcome (ORC-15).
>
> 3. It then answers with status `cancelled` and metadata naming the engine, the signal and the reason.
>
> 4. A pause signal pauses the run and announces only the pause, with no completion announcement, answers with status `paused` and the same metadata keys, and leaves the signal record pending, because that record is the run's resume key.


## What it means

A cancel and a pause are both observed only at the boundary between job
iterations, never mid-node — the job already running always finishes first.
Past that boundary the two diverge in a way that is easy to get backwards.
Cancel is terminal: it announces the cancellation itself, and separately
announces the run as complete (carrying the cancelled status), because
anything that only listens for completion — a session closing out, a parent
run waiting on this one — must hear that the run is over. Pause is not
terminal: it announces only the pause, and nothing tells a completion
listener the run has ended, because it has not. The signal a pause left
behind stays exactly as it was, because that record is the same one a later
resolution resumes against (INT-3).

## Example

The same kind of poll, answered with a cancel and with a pause.

```json title="A run answering a pending cancel" verdict="cancelled"
{ "status": "cancelled", "metadata": { "signal_id": "signal-1", "reason": "operator stopped the run" } }
```

```json title="The same run, answering a pending pause instead" verdict="paused"
{ "status": "paused", "metadata": { "signal_id": "signal-1" } }
```

Only the cancel is followed by a second, completion announcement; the pause
produces exactly one.

## Related rules

- Names: INT-17, ORC-15
- Referenced by: INT-16, INT-17

---

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.