---
id: BR-1
family: RT-BR
level: core
profiles: [runtime]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/rt-br/br-1
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# BR-1 — An edge is gated only when the source actually made a branch decision

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

Gateways decide which paths stay alive, but most edges in a workflow are not branch edges at all. This rule says exactly when a branch decision is allowed to stop an edge, so that everything else keeps flowing.

## The rule

> **Normative.** This is the rule.
>
> 1. An edge is subject to branch gating only when all three of these hold: it leaves a named source port, the source emitted a non-empty active-branch list, and that port is a branch port rather than a value port (BR-2).
>
> 2. Where they hold, the edge is followed if and only if the port's name appears in the source's active-branch list, both sides compared after trimming surrounding whitespace and lower-casing.
>
> 3. In every other case the edge is followed.

## Related rules

- Names: BR-2, BR-3, BR-5
- Referenced by: BR-2, BR-3, BR-5, BR-6, BR-7

---

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.