---
id: ORC-14
family: RT-ORC
level: extended
profiles: [runtime]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/rt-orc/orc-14
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# ORC-14 — A unit of work is claimed atomically

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

Without this, two workers can promote and execute the same unit of work, and a side-effecting node fires twice.

## The rule

> **Normative.** This is the rule.
>
> 1. Claiming a unit of work for execution is atomic with respect to other workers: no unit of work is executed twice because two workers claimed it concurrently.
>
> 2. Queueing a run for execution does not deliver the same work twice.

## Related rules

- Names: ORC-9

---

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.