/**
 * Sampler abstraction for trace sampling decisions.
 * Follows OpenTelemetry Sampler specification patterns.
 *
 * @see https://opentelemetry.io/docs/specs/otel/trace/sdk/#sampler
 */
export type SamplingDecision = "RECORD_AND_SAMPLE" | "DROP";
export type ParentContext = {
    traceId: string;
    spanId: string;
    /** Whether parent came from a remote service (traceparent header) */
    isRemote: boolean;
    /** Parent's sampling decision (from traceparent flags or local span) */
    sampled: boolean;
};
export type SamplingContext = {
    traceId: string;
    name: string;
    parentContext?: ParentContext;
};
export type Sampler = {
    shouldSample(context: SamplingContext): SamplingDecision;
    readonly description: string;
};
/**
 * Always samples - use for development or when you want 100% traces.
 */
export declare function alwaysOnSampler(): Sampler;
/**
 * Never samples - use to disable tracing entirely.
 */
export declare function alwaysOffSampler(): Sampler;
/**
 * Samples based on a probability ratio (0.0 to 1.0).
 * Uses Math.random() for simplicity - not deterministic across services.
 */
export declare function traceIdRatioSampler(ratio: number): Sampler;
export type ParentBasedSamplerOptions = {
    /** Sampler for new traces (no parent) */
    root: Sampler;
    /** Sampler when remote parent was sampled (default: AlwaysOn) */
    remoteParentSampled?: Sampler;
    /** Sampler when remote parent was not sampled (default: AlwaysOff) */
    remoteParentNotSampled?: Sampler;
    /** Sampler when local parent was sampled (default: AlwaysOn) */
    localParentSampled?: Sampler;
    /** Sampler when local parent was not sampled (default: AlwaysOff) */
    localParentNotSampled?: Sampler;
};
/**
 * Makes sampling decisions based on parent span's decision.
 * This is the recommended default sampler for distributed tracing.
 *
 * - Remote parent sampled (traceparent with sampled=1): sample
 * - Remote parent not sampled: don't sample
 * - Local parent sampled: sample
 * - Local parent not sampled: don't sample
 * - No parent: delegate to root sampler
 */
export declare function parentBasedSampler(options: ParentBasedSamplerOptions): Sampler;
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