Module callbacks 

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

Enums

BeforeModelResult

Result from a BeforeModel callback

Type Aliases

AfterAgentCallback

AfterModelCallback

AfterToolCallback

BeforeAgentCallback

BeforeModelCallback

BeforeToolCallback

GlobalInstructionProvider

InstructionProvider