---
id: SCH-37
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-37
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# SCH-37 — A control port declares its lane, never a schema type

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

## The rule

> **Normative.** This is the rule.
>
> 1. `trigger`, `tool` and `loop_back` carry no value, so no JSON Schema type describes them.
>
> 2. A control port declares `x-data-type` and no `type`, and a reserved-port injection assigns the lane by the port's role rather than deriving it.
>
> 3. Control lanes remain full members of the lane vocabulary; what is forbidden is spelling one in `type`.
>
> 4. A lane that carries no value is not offered as a dynamic port type and is not on the list of lanes an author may pick.

## Related rules

- Names: SCH-34, SCH-38
- Referenced by: SCH-10, SCH-32, SCH-34, SCH-38, SCH-40

---

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.