---
id: R9
family: GR-VAL
level: core
profiles: [storage-api]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-val/r9
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# R9 — A node's node type anchor must resolve

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

R9 and R1 are deliberately disjoint: a node type that does not exist is R9's, a node type that exists but has no executor is R1's. One defect earns one report.

## The rule

> **Normative.** This is the rule.
>
> 1. A node's `node_type_id` anchor must resolve to an existing node type.
>
> 2. A node anchored to an unknown node type is refused with `R9_NODE_TYPE_UNKNOWN`, and the error names both the node and the node type it asked for.
>
> 3. A node carrying no anchor is out of scope and is not refused by this rule.

## Why

Recorded under OPEN-6.

## Related rules

- Names: R1.a, R1.b
- Referenced by: R1.a, R1.b, R6.j, R7.e/f

---

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.