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The `@check` attribute in BAML adds validations without raising exceptions if they fail. This allows the validations to be inspected at runtime.

## Usage

### Field Check

**`BAML`**

```baml BAML
class Foo {
  bar int @check(less_than_zero, {{ this < 0 }})
}
```

### Block check

```baml
class Bar {
  baz int
  quux string
  @@check(quux_limit, {{ this.quux|length < this.baz }})
}
```

See [Jinja in Attributes](/ref/attributes/jinja-in-attributes) for a longer description of the Jinja syntax
available in checks.

## Benefits

* **Non-Intrusive Validation**: Allows for validation checks without interrupting the flow of data processing.
* **Runtime Inspection**: Enables inspection of validation results at runtime.

See more in [validations guide](/guide/baml-advanced/checks-and-asserts).