Struct MutableSession 

pub struct MutableSession { /* private fields */ }

Available on crate feature runner only.

MutableSession wraps a session with shared mutable state.

This mirrors ADK-Go’s MutableSession pattern where state changes from events are immediately visible to all agents sharing the same context. This is critical for SequentialAgent/LoopAgent patterns where downstream agents need to read state set by upstream agents via output_key.

Implementations

impl MutableSession

pub fn new(session: Arc<dyn Session>) -> MutableSession

Create a new MutableSession from a session snapshot. The state is copied from the session and becomes mutable.

pub fn apply_state_delta(&self, delta: &HashMap<String, Value>)

Apply state delta from an event to the mutable state. This is called by the Runner when events are yielded.

pub fn append_event(&self, event: Event)

Append an event to the session’s event list. This keeps the in-memory view consistent.

pub fn events_snapshot(&self) -> Vec<Event>

Get a snapshot of all events in the session. Used by the runner for compaction decisions.

pub fn events_len(&self) -> usize

Return the number of accumulated events without cloning the full list.

pub fn conversation_history_for_agent_impl( &self, agent_name: Option<&str>, ) -> Vec<Content>

Build conversation history, optionally filtered for a specific agent.

When agent_name is Some, events authored by other agents (not “user”, not the named agent, and not function/tool responses) are excluded. This prevents a transferred sub-agent from seeing the parent’s tool calls mapped as “model” role, which would cause the LLM to think work is already done.

When agent_name is None, all events are included (backward-compatible).

Trait Implementations

impl Session for MutableSession

fn id(&self) -> &str

fn app_name(&self) -> &str

fn user_id(&self) -> &str

fn state(&self) -> &dyn State

fn conversation_history(&self) -> Vec<Content>

Returns the conversation history from this session as Content items

fn conversation_history_for_agent(&self, agent_name: &str) -> Vec<Content>

Returns conversation history filtered for a specific agent.

fn append_to_history(&self, _content: Content)

Append content to conversation history (for sequential agent support)

fn try_app_name(&self) -> Result<AppName, AdkError>

Returns the application name as a typed AppName.

fn try_user_id(&self) -> Result<UserId, AdkError>

Returns the user identifier as a typed UserId.

fn try_session_id(&self) -> Result<SessionId, AdkError>

Returns the session identifier as a typed SessionId.

fn try_identity(&self) -> Result<AdkIdentity, AdkError>

Returns the stable session-scoped AdkIdentity triple.

impl State for MutableSession

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

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>