Type Alias BeforeModelCallback 

pub type BeforeModelCallback = Box<dyn Fn(Arc<dyn CallbackContext>, LlmRequest) -> Pin<Box<dyn Future<Output = Result<BeforeModelResult, AdkError>> + Send>> + Send + Sync>;

Core traits and types.

Always available regardless of feature flags. Includes:

• Agent - The fundamental trait for all agents
• Tool / Toolset - For extending agents with capabilities
• Session / State - For managing conversation context
• Event - For streaming agent responses
• AdkError / Result - Unified error handling Callback invoked before a model call. Can modify the request or skip the call entirely.

Aliased Type

pub struct BeforeModelCallback(/* private fields */);