---
id: CMP-3
family: RT-CMP
level: core
profiles: [runtime]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/rt-cmp/cmp-3
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# CMP-3 — Structure preconditions are checked before anything is planned

*RT-CMP (Part II) · level: core · profiles: runtime · added in 1.0*

The cheapest checks run first, so a workflow that cannot possibly execute is rejected before any graph work happens.

## The rule

> **Normative.** This is the rule.
>
> 1. Before any graph is built, compilation checks, in order: the workflow has an identifier; it has at least one node; and then, per node in definition order, that the node has an identifier and that it has a type.
>
> 2. The first failure refuses compilation, and the failure names which precondition failed and, where the failure is a node's, which node.


## What it means

The cheapest checks run first, and in a fixed order: the workflow's own
identifier, then whether it has any node at all, then — per node, in
definition order — that the node has an identifier and that it has a type.
A workflow missing its own identifier is refused before any node is
examined at all, whatever shape those nodes are in. Within the per-node
pass, the first node in definition order that fails is the one named in the
failure; a later node's problems are never reported instead.

## Example

```json title="A workflow with no identifier" verdict="given"
{ "nodes": [{ "id": "node1", "type": "text_input" }] }
```

```json title="What compilation reports" verdict="refused"
"Workflow must have an ID"
```

The same shape, with an identifier but a node missing its type:

```json title="A node with no declared type" verdict="given"
{ "id": "test_workflow", "nodes": [{ "id": "node1" }] }
```

```json title="What compilation reports" verdict="refused"
"Node node1 must have a type"
```

The message names the node — `node1` — not merely that some node failed.

## Related rules

- Names: CMP-1
- Referenced by: CMP-1

---

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.