---
id: R3
family: GR-VAL
level: core
profiles: [storage-api]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-val/r3
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# R3 — Every edge carries a unique id

*GR-VAL (Part I) · level: core · profiles: storage-api · added in 1.0*

## The rule

> **Normative.** This is the rule.
>
> 1. Every edge in a workflow must carry an `id`, and edge `id`s must be unique within the workflow.
>
> 2. An edge with no `id` is refused with `R3_EDGE_MISSING_ID`, a repeated `id` with `R3_EDGE_DUPLICATE_ID`, and in either case the save does not take effect.
>
> 3. An implementation may mint an id for an edge that lacks one while reading an already-stored definition; that tolerance is for legacy data only and never relaxes the requirement at save.

## Why

Recorded under OPEN-5.

---

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.