Method workflow_with_token_budget

core/src/agent_api.rs:1001–1032

Like [`workflow`](Self::workflow) but with a hard token ceiling shared across every step. The cap is a best-effort *soft* cost ceiling — under a wide fan-out a few in-flight turns can race past it before the shared ledger catches up (see [`WorkflowBudget`](crate::orchestration::WorkflowBudget)).

(
        &self,
        limit_tokens: Option<u64>,
    )

    /// wide fan-out a few in-flight turns can race past it before the shared
    /// ledger catches up (see [`WorkflowBudget`](crate::orchestration::WorkflowBudget)).
    pub fn workflow_with_token_budget(
        &self,
        limit_tokens: Option<u64>,
    ) -> crate::orchestration::Workflow {
        use crate::budget::BudgetGuard;

        // One shared ledger for the whole workflow, wrapping the session's own
        // budget guard (if any) so a host's per-tenant accounting keeps working.
        let mut budget = crate::orchestration::WorkflowBudget::new(limit_tokens);
        if let Some(inner) = self.config.budget_guard.clone() {
            budget = budget.with_inner(inner);
        }
        let budget = Arc::new(budget);

        // Install the shared ledger as the child runs' budget guard so every
        // step's per-turn LLM accounting feeds it.
        let mut parent = self.parent_run_context();
        parent.budget_guard = Some(Arc::clone(&budget) as Arc<dyn BudgetGuard>);
        let executor: Arc<dyn crate::orchestration::AgentExecutor> =
            Arc::new(self.build_task_executor(parent));

        let mut builder = crate::orchestration::Workflow::builder(executor)
            .with_root_id(format!("wf-{}", self.session_id))
            .with_budget(Arc::clone(&budget));
        if let Some(store) = self.session_store.clone() {
            builder = builder.with_store(store);
        }
        if let Some(step_events) = self.tool_context.agent_event_tx.clone() {
            builder = builder.with_step_events(step_events);
        }
        builder.build()
    }

    /// Build the [`ChildRunContext`](crate::child_run::ChildRunContext) that
    /// orchestrated / delegated child runs inherit from this session.