/**
 * Task lifecycle span helpers.
 *
 * Tracks the full task state machine:
 * TASK_CREATED → TASK_STARTED → TASK_BLOCKED → TASK_PROGRESS
 * Terminal states: TASK_COMPLETED | TASK_FAILED | TASK_CANCELLED
 *
 * One span per task. Optionally parented to an agent span.
 */
import type { Span, SpanAttributes } from '../types.js';
import type { RuntimeTracer } from '../tracer.js';
/** Context supplied when starting a task lifecycle span. */
export interface TaskSpanContext {
    /** Task ID (unique). */
    readonly taskId: string;
    /** Optional agent ID that owns this task. */
    readonly agentId?: string | undefined;
    /** Human-readable task description. */
    readonly description: string;
    /** Task scheduling priority. */
    readonly priority: number;
    /** Trace ID for cross-span correlation. */
    readonly traceId: string;
    /**
     * Optional parent span ID for nesting under an agent span.
     * When provided, this task span becomes a child of the agent span.
     */
    readonly parentSpanId?: string | undefined;
}
/** Phase transitions recordable on a task lifecycle span. */
export type TaskPhase = 'started' | 'blocked' | 'progress';
/** Result context supplied when ending a task lifecycle span. */
export interface TaskSpanEndContext {
    /** Final outcome of the task. */
    readonly outcome: 'completed' | 'failed' | 'cancelled';
    /** Duration of the task in milliseconds. */
    readonly durationMs: number;
    /** Error description when outcome is 'failed'. */
    readonly error?: string | undefined;
    /** Cancel reason when outcome is 'cancelled'. */
    readonly reason?: string | undefined;
}
/**
 * Start a task lifecycle span.
 *
 * @param tracer - RuntimeTracer instance.
 * @param ctx - Context from TASK_CREATED event.
 */
export declare function startTaskSpan(tracer: RuntimeTracer, ctx: TaskSpanContext): Span;
/**
 * Record a task phase transition event.
 *
 * @param span - The active task lifecycle span.
 * @param phase - The phase reached.
 * @param attrs - Optional additional attributes.
 */
export declare function recordTaskPhase(span: Span, phase: TaskPhase, attrs?: SpanAttributes): void;
/**
 * End a task lifecycle span.
 *
 * @param span - The span returned by `startTaskSpan`.
 * @param ctx - Task lifecycle end context.
 */
export declare function endTaskSpan(span: Span, ctx: TaskSpanEndContext): void;
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