---
id: EXPO-6
family: GR-EXPO
level: core
profiles: [storage-api, editor-client]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-expo/expo-6
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# EXPO-6 — A processor's exposure suggestion is authoring input only

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

A processor may suggest that a port ship hidden. That suggestion is consumed once, when a node type's exposure values are first written, and never again, so a consumer reading a node type's published metadata is reading decisions, not suggestions.

## The rule

> **Normative.** This is the rule.
>
> 1. The `x-exposed-by-default` schema extension is consumed at authoring time only: when seeding an author's exposure controls, and when a node type's stored exposure values are first derived from a processor's schema.
>
> 2. It must never be consulted when a workflow runs, and no execution-time decision may depend on it.
>
> 3. Published node metadata reports exposure as it stands in the node type's stored configuration (EXPO-7), never a processor's own suggestion; a processor declaring the extension therefore cannot change what an already-configured node type publishes.


## What it means

A processor's exposure suggestion is read exactly once: when a node type is
first derived from it. After that read, the suggestion is inert — changing
the processor's schema later does not change what an already-derived node
type publishes, because nothing at execution or publication time goes back
to ask the processor again. What a node type reports is always its own
stored decision (EXPO-7), never a live read of the processor.

## Example

A processor's schema offers no opinion on one port and asks for the other to
ship hidden.

```json title="The processor's own schema for two of its ports"
{ "visible_in": { "type": "string" }, "hidden_in": { "type": "string", "x-exposed-by-default": false } }
```

```json title="What the node type stores for hidden_in, once, at derivation" verdict="hidden"
{ "exposed_by_default": false }
```

`visible_in` gets no such key at all — the derivation writes the flag only
where it diverges from exposed. From that point on, a change to the
processor's own schema reaches neither entry.

## Related rules

- Names: EXPO-5, EXPO-7
- Referenced by: EXPO-5, EXPO-7, EXPO-8, EXPO-16

---

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.