Attribute Macro skill 

#[skill]

Attribute macro for defining A2A skills with metadata.

This macro generates the SkillMetadata and implements the RegisteredSkill trait for the annotated struct, making it usable with the radkit agent builder.

Required Parameters

• id: A unique identifier for the skill (String)
• name: A human-readable name for the skill (String)
• description: A detailed description of what the skill does (String)

Optional Parameters

• tags: Array of keywords describing the skill’s capabilities (default: [])
• examples: Array of example prompts or scenarios (default: [])
• input_modes: Array of supported input MIME types (default: [])
• output_modes: Array of supported output MIME types (default: [])

MIME Type Validation

The macro validates input_modes and output_modes against a list of common MIME types. If an invalid type is provided, a compile error will be generated with suggestions.

Example

use radkit::prelude::*;

#[skill(
    id = "summarize_text",
    name = "Text Summarizer",
    description = "Summarizes long text documents into concise summaries",
    tags = ["text", "summarization", "nlp"],
    examples = [
        "Summarize this article",
        "Give me a brief summary of this document"
    ],
    input_modes = ["text/plain", "text/markdown"],
    output_modes = ["text/plain", "application/json"]
)]
pub struct SummarizeTextSkill;

#[async_trait]
impl SkillHandler for SummarizeTextSkill {
    async fn on_request(
        &self,
        task_context: &mut TaskContext,
        context: &Context,
        runtime: &dyn Runtime,
        content: Content,
    ) -> Result<OnRequestResult, AgentError> {
        // Implementation here
        Ok(OnRequestResult::Completed {
            message: Some(Content::text("Summary here")),
            artifacts: vec![],
        })
    }
}

Generated Code

The macro generates:

1. A static SkillMetadata constant named {STRUCT_NAME}_METADATA
2. An implementation of RegisteredSkill trait for the struct

This allows the skill to be registered with an agent using .with_skill():

let agent = AgentBuilder::new()
    .with_skill(SummarizeTextSkill)
    .build(runtime)?;