# Required Root Information

Core OSCAL requires somne content to be present all OSCAL artifacts. This is crtical to consistent processing. 

### Root Element and Root-Level Universally Unique Identifier

The root element must be one of the case-sensitive OSCAL model names:

- `catalog`
- `profile`
- `mapping-collection` (OSCAL version >=1.2.0)
- `component-definition`
- `system-security-plan`
- `plan-of-action-and-milestones`
- `assessment-plan`
- `assessment-results`

It must be immediately followed by root-level (document-level) UUID.

In JSON and YAML, the UUID is a child of the root element. In XML it is an attribute of the root element. 

<div class="callout">
<strong>Additional XML Requirement</strong>
  
OSCAL XML artifacts must include an XML declaration above the root element, and XML namespace declaration as an attribute of the root element. 
</div>

#### XML Example
```xml
<?xml version="1.0" encoding="UTF-8"?>
<system-security-plan 
     xmlns="http://csrc.nist.gov/ns/oscal/1.0" 
     uuid="11111111-2222-4000-8000-000000000000">
</catalog>
```

#### JSON Example

```json
{
  "system-security-plan": {
    "uuid": "11111111-2222-4000-8000-000000000000"
    }
}
```

#### YAML Example
```yaml
system-security-plan:
  uuid: 11111111-2222-4000-8000-000000000000
```
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