/**
 * CAELTrace — Contracted Agent-Environment Loop artifact schema (Phase 1).
 *
 * JSONL entry format with hash-chain integrity. Each line is one event.
 *
 * Hash mode (Option C, 2026-04-20 SECURITY wave): the chain hash
 * function is configurable between FNV-1a (default, fast, non-
 * cryptographic) and SHA-256 (opt-in via ContractConfig.useCryptographicHash).
 * Mode is threaded into hashCAELEntry + verifyCAELHashChain, and
 * written into cael.init.payload.hashMode for trace self-identification
 * (Prereq 3 — prevents silent-downgrade and mid-trace mode tampering).
 *
 * See: packages/engine/src/simulation/sha256.ts for the hash primitives.
 */
import { type HashMode } from './sha256';
import { hashCAELEntry } from './hashes';
export { hashCAELEntry };
export type CAELTraceEvent = 'init' | 'step' | 'interaction' | 'solve' | 'final';
export interface CAELTraceEntry {
    version: 'cael.v1';
    runId: string;
    index: number;
    event: CAELTraceEvent;
    timestamp: number;
    simTime: number;
    prevHash: string;
    hash: string;
    payload: Record<string, unknown>;
}
export type CAELTrace = CAELTraceEntry[];
export declare function encodeCAELValue(value: unknown): unknown;
export declare function decodeCAELValue(value: unknown): unknown;
export declare function toCAELJSONL(trace: CAELTrace): string;
export declare function parseCAELJSONL(jsonl: string): CAELTrace;
/**
 * Verify the hash chain of a CAEL trace under a given mode.
 *
 * Mode semantics (Option C, Prereq 3):
 *   - If `mode` is provided, every entry's hash must both (a) equal
 *     the re-computed hashCAELEntry output under that mode and
 *     (b) have a shape consistent with that mode. Any entry whose
 *     hash shape contradicts the declared mode is a mid-trace
 *     tamper — the verifier rejects with a specific error.
 *   - If `mode` is omitted, infer from the trace: prefer the mode
 *     recorded in `trace[0].payload.hashMode`, else fall back to
 *     'fnv1a' (back-compat for pre-Option-C traces).
 *
 * The shape check is the Prereq 3 guard: an adversary who replaces a
 * single event's hash with a different-mode hash (even with a
 * matching chain recomputation) is caught before the expected-hash
 * comparison runs.
 */
export declare function verifyCAELHashChain(trace: CAELTrace, mode?: HashMode): {
    valid: boolean;
    brokenAt?: number;
    reason?: string;
};
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