---
id: R4.e
family: GR-VAL
level: extended
profiles: [storage-api]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-val/r4-e
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# R4.e — An exposure name may not collide with a reserved runtime name

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

R4.a's alphabet admits names beginning with underscores, which is where the runtime's own injected parameters live. Without this rule an author could claim one of them and shadow it.

## The rule

> **Normative.** This is the rule.
>
> 1. A workflow exposure entry's `name` must not be a name the runtime reserves for parameters it injects into a workflow's manifest; `__interrupt_id__` is such a name.
>
> 2. A reserved name is refused with `R4_NAME_RESERVED` at `schema.{side}.{index}`, on the input side and the output side alike.

## Related rules

- Names: R4.a
- Referenced by: R4.a

---

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.