/**
 * Content-addressed step identity (Design Law 1).
 *
 * step_key = hash(step_kind, step_name)[:16] + ':' + occurrence_index
 *
 * where occurrence_index is the count of prior calls with the same
 * (kind, name) pair in this execution. A memoized result may be returned
 * only if the stored key matches the key computed at the call site —
 * a mismatch means workflow control flow drifted between runs, and the
 * cached output belongs to a different call site.
 */
/** Step-kind identifiers used in key hashing (aligned with proto StepType names). */
export type StepKind = 'ACTIVITY' | 'TIMER' | 'SIGNAL_WAIT' | 'SIDE_EFFECT';
/** First 16 hex chars of sha256("<kind>\n<name>"). */
export declare function stepKeyHash(stepKind: StepKind, stepName: string): string;
/**
 * Tracks per-(kind, name) occurrence counts for one workflow execution and
 * produces the full step_key for each durable call in program order.
 */
export declare class StepKeyTracker {
    private occurrences;
    next(stepKind: StepKind, stepName: string): string;
}
/**
 * Thrown when a checkpointed step's identity does not match the step the
 * workflow code is executing at that sequence position — i.e. control flow
 * up to the first pending step was not reproducible. The workflow is failed
 * loudly rather than silently returning the wrong memoized value.
 */
export declare class NonDeterminismError extends Error {
    readonly stepSeq: number;
    readonly storedKey: string;
    readonly computedKey: string;
    constructor(stepSeq: number, storedKey: string, computedKey: string, detail?: string);
}
/**
 * Validate a stored checkpoint against the call site's computed identity.
 *
 * - Stored key present → must equal the computed key exactly.
 * - Stored key absent (checkpoint written before step_key existed) →
 *   fall back to step_name equality and warn, per the P0.1 back-compat rule.
 */
export declare function validateStepKey(args: {
    stepSeq: number;
    storedKey: string | undefined;
    storedName: string | undefined;
    computedKey: string;
    stepKind: StepKind;
    stepName: string;
}): void;