---
id: SCH-34
family: GR-SCHEMA
level: core
profiles: [storage-api, editor-client]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-schema/sch-34
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# SCH-34 — A property's type is a JSON Schema type, not a port lane

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

The two vocabularies overlap on four words, which is why a lane name written into `type` looks correct, derives the wrong lane, and is caught by nothing.

## The rule

> **Normative.** This is the rule.
>
> 1. A property's `type` is one of JSON Schema's seven type words, or an array whose every member is one.
>
> 2. It is never a port lane.
>
> 3. A schema that spells a lane in `type` is malformed, on the input side and the output side alike: the lane derivation answers the miss with the sink and reports nothing, so the only symptom is a port of the wrong lane.
>
> 4. An implementation states this constraint where a schema is declared, so an offending schema is caught before it ships rather than after a port is drawn from it.

## Related rules

- Names: SCH-9, SCH-10, SCH-35, SCH-37
- Referenced by: SCH-9, SCH-10, SCH-35, SCH-37

---

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.