---
id: EXPO-12
family: GR-EXPO
level: core
profiles: [storage-api, runtime]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-expo/expo-12
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# EXPO-12 — Control outputs are never stripped

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

## The rule

> **Normative.** This is the rule.
>
> 1. The reserved control outputs `active_branches` and `state_update` are never removed from a node's result by exposure stripping.
>
> 2. They are the engine's own channel, not ports an author shows or hides, and branching and state merging depend on them arriving intact.


## What it means

Control outputs are exempt from every lever that strips an ordinary port —
the node type's own default, an instance override, all of it. They are not
something an author shows or hides at all; they are the engine's own
channel, and branching and state merging depend on them arriving whole every
time, whatever exposure a workflow otherwise records for that node.

## Example

A node's type marks every one of its outputs — `active_branches`,
`state_update`, and an ordinary port — hidden, and the workflow's own
instance override hides `state_update` again on top of that: the least
favourable exposure available for all three.

```json title="What the node produced" verdict="produced"
{"state_update": {"iterator": {"index": 1}}, "active_branches": "true", "debug": "internal trace"}
```

```json title="What the result delivers" verdict="kept"
{"state_update": {"iterator": {"index": 1}}, "active_branches": "true"}
```

`debug`, an ordinary output hidden the same way, is the one key stripping
removes.

## Related rules

- Names: EXPO-11
- Referenced by: EXPO-11, EXPO-14, DATA-8

---

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.