---
id: EDGE-4
family: GR-EDGE
level: core
profiles: [storage-api]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-edge/edge-4
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# EDGE-4 — A loopback edge targets the port named loop_back

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

## The rule

> **Normative.** This is the rule.
>
> 1. An edge is a loopback edge when, and only when, its target handle ends with `-input-loop_back`.
>
> 2. The reserved port name is `loop_back`: a handle ending with `-input-loopback` is an ordinary edge.

## Related rules

- Names: EDGE-1
- Referenced by: EDGE-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.