---
id: CFG-17
family: GR-CFG
level: extended
profiles: [storage-api]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-cfg/cfg-17
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# CFG-17 — A hidden port cannot be filled through the bundle

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

Decomposition filters on `connectable` alone, so a hidden port's key can survive the unpacking. Resolution then applies the exposure gate a second time. Two guards, one outcome: a hidden port is not fillable, by any route.

## The rule

> **Normative.** This is the rule.
>
> 1. Decomposition of the unified `input` port (CFG-16) admits a key on the strength of `connectable` alone.
>
> 2. A value that reaches a hidden connectable port this way is still discarded when the parameter is resolved, because priority 1 requires the port to be exposed (CFG-4).
>
> 3. Bundling a value must never fill a port that could not be wired directly.

## Related rules

- Names: CFG-4, CFG-16, EXPO-10
- Referenced by: CFG-16, EXPO-10

---

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.