Trait State 

pub trait State: Send + Sync {
    // Required methods
    fn get(&self, key: &str) -> Option<Value>;
    fn set(&mut self, key: String, value: Value);
    fn all(&self) -> HashMap<String, Value>;
}

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 Mutable session state with key-value storage.

Implementations persist state across turns within a session.

Required Methods

fn get(&self, key: &str) -> Option<Value>

Returns the value for the given key, or None if not present.

fn set(&mut self, key: String, value: Value)

Set a state value. Implementations should call validate_state_key and reject invalid keys (e.g., by logging a warning or panicking).

fn all(&self) -> HashMap<String, Value>

Returns all key-value pairs in the state.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl State for MutableSession