Struct Session 

pub struct Session {

    pub id: String,
    pub title: String,
    pub pinned: bool,
    pub title_version: u64,
    pub metadata_version: u64,
    pub kind: SessionKind,
    pub parent_session_id: Option<String>,
    pub root_session_id: String,
    pub spawn_depth: u32,
    pub messages: Vec<Message>,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
    pub task_list: Option<TaskList>,
    pub pending_question: Option<PendingQuestion>,
    pub model: String,
    pub model_ref: Option<ProviderModelRef>,
    pub reasoning_effort: Option<ReasoningEffort>,
    pub metadata: HashMap<String, String>,
    pub token_budget: Option<TokenBudget>,
    pub token_usage: Option<TokenBudgetUsage>,
    pub conversation_summary: Option<ConversationSummary>,
    pub prompt_snapshot: Option<PromptSnapshot>,
    pub compression_events: Vec<CompressionEvent>,
    pub compression_instructions: Option<String>,
    pub agent_runtime_state: Option<AgentRuntimeState>,
    pub force_manual_compression: Option<String>,
}

A complete conversation session with state management.

Fields

id: String

title: String

pinned: bool

title_version: u64

metadata_version: u64

Authoritative UI metadata revision. Bumped by every authoritative metadata write (title / pinned / future replayable metadata fields). Runtime / non-authoritative paths must not bump this; they read it to detect when their session struct holds stale UI metadata.

kind: SessionKind

parent_session_id: Option<String>

root_session_id: String

spawn_depth: u32

messages: Vec<Message>

created_at: DateTime<Utc>

updated_at: DateTime<Utc>

task_list: Option<TaskList>

pending_question: Option<PendingQuestion>

model: String

model_ref: Option<ProviderModelRef>

reasoning_effort: Option<ReasoningEffort>

metadata: HashMap<String, String>

token_budget: Option<TokenBudget>

token_usage: Option<TokenBudgetUsage>

conversation_summary: Option<ConversationSummary>

prompt_snapshot: Option<PromptSnapshot>

compression_events: Vec<CompressionEvent>

compression_instructions: Option<String>

Custom instructions for conversation summarization at the session level. Overrides config-level compression_instructions when set.

agent_runtime_state: Option<AgentRuntimeState>

force_manual_compression: Option<String>

Runtime-only flag: when set, the next mid-turn compression check should force compression regardless of threshold. Set by compact_context tool.

Implementations

impl Session

pub fn new(id: impl Into<String>, model: impl Into<String>) -> Session

pub fn new_child( id: impl Into<String>, root_session_id: impl Into<String>, model: impl Into<String>, title: impl Into<String>, ) -> Session

pub fn add_message(&mut self, message: Message)

pub fn compact_oversized_tool_messages(&mut self) -> usize

pub fn clear_derived_context_state(&mut self)

Clear all ephemeral/derived state that should not persist across turns.

Resets token usage, compression state, previous response metadata, and message compression flags. Typically called before a truncation or when refreshing session state for a new execution.

pub fn set_task_list(&mut self, task_list: TaskList)

pub fn update_task_item( &mut self, item_id: &str, status: TaskItemStatus, notes: Option<&str>, criteria_met: Option<&[String]>, ) -> Result<String, String>

pub fn format_task_list_for_prompt(&self) -> String

pub fn set_pending_question( &mut self, tool_call_id: String, tool_name: String, question: String, options: Vec<String>, allow_custom: bool, )

pub fn clear_pending_question(&mut self)

pub fn has_pending_question(&self) -> bool

Trait Implementations

impl Clone for Session

fn clone(&self) -> Session

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Session

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Session

fn deserialize<__D>( __deserializer: __D, ) -> Result<Session, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for Session

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.