/**
 * Shared opaque-reference schema for v0.14.1 observational extensions
 * (a2a-handoff, cli-execution, lifecycle-observation).
 *
 * Generalizes the single-prefix precedent established by ReceiptRefSchema
 * (sha256:<64 hex>) and CredentialRefSchema ((sha256|hmac-sha256):<64 hex>)
 * into a multi-prefix grammar that uniformly rejects email shapes, raw human
 * names in any language, numeric strings, inline JSON, and free text without
 * language-specific or numeric-specific heuristics.
 *
 * Grammar (binding):
 *   - String, max UTF-8 byte length 256 by default (per call site).
 *   - MUST NOT contain whitespace.
 *   - MUST NOT contain `@` (rejects email shapes).
 *   - MUST NOT start with JSON-structural characters: `{` `[` `"`.
 *   - MUST start with one of the recognized reference prefixes:
 *       `ref:`  `urn:`  `did:`  `sha256:`  `peac:`  `https://`
 *   - When the value starts with `sha256:`, the suffix MUST be exactly
 *     64 lowercase hex characters (matches the canonical PEAC digest grammar
 *     in `wire-02-extensions/shared-validators.ts`).
 *   - When the value starts with `https://`, the URL MUST contain at least
 *     one additional non-whitespace character after the scheme.
 *
 * Byte-length enforcement uses UTF-8 byte length (TextEncoder) rather than
 * JavaScript string length (which counts UTF-16 code units), so multi-byte
 * payloads are correctly bounded.
 */
import { z } from 'zod';
export declare const OPAQUE_REF_PREFIXES: readonly ["ref:", "urn:", "did:", "sha256:", "peac:", "https://"];
export interface OpaqueRefSchemaOptions {
    maxBytes?: number;
    /** Stable diagnostic code attached to every refinement message. */
    errorCode?: string;
}
/**
 * Construct an opaque-reference Zod schema with grammar enforcement.
 * Default max is 256 UTF-8 bytes; pass `maxBytes` to override per call site.
 * Pass `errorCode` to attach a stable code (e.g. `lifecycle.opaque_ref_grammar_violation`)
 * to every rejection message; downstream validators map this to their own
 * structured error reporting.
 */
export declare function createOpaqueRefSchema(options?: OpaqueRefSchemaOptions): z.ZodString;
export declare const OpaqueRefSchema: z.ZodString;
export type OpaqueRef = z.infer<typeof OpaqueRefSchema>;
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