Struct AgentRunner 

pub struct AgentRunner {
    pub event_sender: Sender<AgentEvent>,
    pub cancel_token: CancellationToken,
    pub status: AgentStatus,
    pub started_at: DateTime<Utc>,
    pub completed_at: Option<DateTime<Utc>>,
    pub last_budget_event: Option<AgentEvent>,
    pub last_critical_events: Vec<AgentEvent>,
    pub last_tool_name: Option<String>,
    pub last_tool_phase: Option<String>,
    pub last_event_at: Option<DateTime<Utc>>,
    pub round_count: u32,
    pub run_id: String,
}

Runner that manages agent execution for a session.

Each active agent run has an associated AgentRunner that coordinates event broadcasting, cancellation, and status tracking.

Event Broadcasting

Uses a broadcast channel to support multiple subscribers watching the same agent run simultaneously.

Cancellation

Provides a cancellation token that can be used to gracefully stop an in-progress agent execution.

Fields

event_sender: Sender<AgentEvent>

Broadcast sender for agent events.

Allows multiple clients to subscribe to agent events via event_sender.subscribe().

cancel_token: CancellationToken

Cancellation token for graceful shutdown.

When triggered, the agent should stop execution at the next safe point.

status: AgentStatus

Current status of the agent run.

started_at: DateTime<Utc>

Timestamp when the run was started.

completed_at: Option<DateTime<Utc>>

Timestamp when the run completed (if finished).

last_budget_event: Option<AgentEvent>

Last token budget event to replay for new subscribers.

When a new client subscribes to an ongoing run, this allows them to receive the most recent token usage info.

last_critical_events: Vec<AgentEvent>

Small ring of critical state events (TaskListUpdated, SubSession*, etc.) cached for replay to late/reconnecting subscribers.

Bounded to [CRITICAL_EVENTS_CAPACITY] entries; oldest are evicted.

last_tool_name: Option<String>

Name of the most recently executed tool (if any). Updated live during execution for diagnostic visibility.

last_tool_phase: Option<String>

Phase of the most recently executed tool: “begin”, “finished”, or “error”. Updated live during execution for diagnostic visibility.

last_event_at: Option<DateTime<Utc>>

Timestamp of the last event received during this run. Updated live during execution for liveness checks.

round_count: u32

Number of completed rounds (turns) so far. Updated live during execution for progress tracking.

run_id: String

Unique identifier for this execution run. Generated fresh for every try_reserve_runner call so that frontend SSE events can be matched to the correct run even across reconnects.

Implementations

impl AgentRunner

pub const EVENT_CHANNEL_CAPACITY: usize = 1000

Broadcast channel capacity for agent events.

pub const CRITICAL_EVENTS_CAPACITY: usize = 32

Maximum number of critical events cached for late-subscriber replay.

pub fn new() -> Self

Create a new agent runner with default settings.

Initializes a broadcast channel, a fresh cancellation token, and Pending status.

pub fn push_critical_event(&mut self, event: AgentEvent)

Push a critical event into the bounded replay cache.

If the cache is full, the oldest entry is evicted.

Trait Implementations

impl Clone for AgentRunner

fn clone(&self) -> AgentRunner

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for AgentRunner

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

Formats the value using the given formatter.

impl Default for AgentRunner

fn default() -> Self

Returns the “default value” for a type.