Struct Tcb 

pub struct Tcb {

    pub id: TaskId,
    pub parent: Option<TaskId>,
    pub children: BTreeSet<TaskId>,
    pub state: TaskLifecycle,
    pub runnable_cause: RunnableCause,
    pub budget: BudgetLedger,
    pub wait_set: Option<DurableWaitSet>,
    pub caps: Vec<CompactString>,
    pub capabilities: Vec<Capability>,
    pub proc: Option<ProcInfo>,
    pub supervision: SupervisionPolicy,
    pub supervision_events: Vec<SupervisionEvent>,
    pub detached: bool,
    pub child_budget_remaining: Option<ResourceBudget>,
    pub budget_grant: Option<BudgetGrant>,
    pub mailbox: Mailbox,
}

One schedulable entity. The root loop and every sub-agent are uniform Tcbs.

Fields

id: TaskId

parent: Option<TaskId>

children: BTreeSet<TaskId>

spc_002: child task ids spawned under this task. Populated by TaskTable insertion (spc_002-05); empty for leaf tasks and for every task predating recursive spawn.

state: TaskLifecycle

runnable_cause: RunnableCause

Why a Ready child entered the unified local runnable set.

budget: BudgetLedger

wait_set: Option<DurableWaitSet>

Canonical recoverable wait state.

caps: Vec<CompactString>

Capability ids permitted to this task (mirrors AgentProcess.permitted_capability_ids).

capabilities: Vec<Capability>

spc_004 debt closure: this task’s own held Capability grants (spc_004’s resource/ action-scoped shape) — what a spawn from this task may legally attenuate into. Empty by default; only set when IsolationManifest.requested_capabilities (spc_004) was non-empty at spawn time.

proc: Option<ProcInfo>

Sub-agent identity for child tasks; None for the root loop.

supervision: SupervisionPolicy

spc_002-07: read by terminate() (spc_008-04) when this task’s own terminal transition commits, to decide what happens to any still-running children.

supervision_events: Vec<SupervisionEvent>

Durable attempt-level failure history. Logical-task state may continue after a relaunch.

detached: bool

spc_008-05: when true, this task is exempt from cancel_subtree/cancel_children — it (and its own descendants) are never cancelled as a side effect of an ancestor’s cancellation or termination. false by default (existing behavior unchanged).

child_budget_remaining: Option<ResourceBudget>

spc_005: this task’s own currently-grantable budget pool for its children — reserve()’s parent_remaining argument. None (the default) means no hierarchical budget is in play on this task, so spawn-time budget checks are skipped entirely and behavior is unchanged from before spc_005.

budget_grant: Option<BudgetGrant>

spc_005: the grant this task itself received from its parent at spawn time, if the spawner set IsolationManifest.requested_budget. None for the root and for any child spawned without a hierarchical budget request.

mailbox: Mailbox

spc_006-03: this task’s point-to-point inbox. Empty by default; populated via TaskTable::send_message.

Implementations

impl Tcb

pub fn root(id: impl Into<TaskId>, budget: SchedulerBudget) -> Self

The root loop task. Constructed from the runtime task at Start.

pub fn spawned(manifest: &IsolationManifest, budget: SchedulerBudget) -> Self

A sub-agent task spawned under the root, seeded Running, carrying the manifest’s process identity. The single source of truth for what the AgentProcess view exposes.

pub fn spawned_in( manifest: &IsolationManifest, budget: SchedulerBudget, state: TaskLifecycle, parent: Option<TaskId>, ) -> Self

The same child, seeded in an explicit lifecycle state under an explicit parent.

The acknowledged spawn arc is PendingLaunch → Starting → Running(ack). Callers that have already observed the host launch use Self::spawned; callers that are publishing a launch use this constructor with its explicit lifecycle state.

spc_002-02: parent is no longer hardcoded to root — callers must supply the real caller. This card does not derive that caller from syscall causation (spc_002-04); every call site still passes Some("root") explicitly, preserving today’s behavior byte-for-byte.

Trait Implementations

impl Clone for Tcb

fn clone(&self) -> Tcb

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Tcb

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

Formats the value using the given formatter.