---
id: SCH-45
family: GR-SCHEMA
level: extended
profiles: [storage-api, editor-client]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-schema/sch-45
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# SCH-45 — A stored lane overlay is checked when it is stored

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

The overlay is the one piece of the vocabulary a site writes by hand, so it is the one place a mistake should be reported to the person making it.

## The rule

> **Normative.** This is the rule.
>
> 1. Where an implementation lets a site store its own lane overlay (SCH-10.a), the overlay is checked when it is stored: a structurally malformed overlay is refused then, not accepted and discovered when something tries to render it.
>
> 2. This is distinct from a well-formed declaration the vocabulary declines on its own terms — a shape naming a reserved lane id is ignored rather than fatal (SCH-44).
>
> 3. A port shape's JSON Schema is not part of this specification's keyspace: an implementation must not refuse a schema keyword merely because it does not recognise it.

## Related rules

- Names: SCH-10.a, SCH-44, SCH-46

---

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.