@description / @@description

The @description attribute in BAML provides additional context to fields or values in prompts. This can help the LLM understand the intended use or meaning of a field or value.

Prompt Impact

Without @description

1
class MyClass {
2
  property1 string
3
}

ctx.output_format:

{
  property1: string
}

With @description

1
class MyClass {
2
  property1 string @description("The name of the object")
3
}

ctx.output_format:

{
  // The name of the object
  property1: string
}

Prompt Impact (enum - value)

Without @description

1
enum MyEnum {
2
  Value1
3
  Value2
4
}

ctx.output_format:

MyEnum
---
Value1
Value2

With @description

1
enum MyEnum {
2
  Value1 @description("The first value")
3
  Value2 @description("The second value")
4
}

ctx.output_format:

MyEnum
---
Value1 // The first value
Value2 // The second value

Prompt Impact (enum)

1
enum MyEnum {
2
  Value1
3
  Value2
4
5
  @@description("This enum represents status codes")
6
}

ctx.output_format:

MyEnum: This enum represents status codes
---
Value1
Value2