@child

Generated Markdown for references/fact_dec_child.md.

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# @child

`@child("kind")` declares a field that holds a **single** nested block of the given kind. Make the field optional (`Type?`) when the child may be omitted. Contrast with `@children`, which holds a list.

```wcl
@block("service") type Service {
  @child("metadata") meta: Metadata?
}

@block("metadata") type Metadata {
  owner: utf8
}

service api {
  metadata { owner = "platform" }
}
```

## Related

- [@children](../references/fact_dec_children.md)

- [@block](../references/fact_dec_block.md)

- [Block Schema](../references/concept_block_schema.md)

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