/**
 * What MCP results redact before a model or client sees them. The redaction
 * itself runs in `build-server.ts`; an opted-in action's advertised output
 * contract is derived through the same rules (`action-output-contract.ts`),
 * so both read them from here. Server logs that show a thrown value read it
 * through the same string check.
 */
/**
 * Replaces a string carrying an embed start reference, so a reader sees
 * that a value was hidden rather than finding its key missing.
 */
export declare const HIDDEN_EMBED_URL = "[hidden embed URL]";
/** Replaces a value already being serialized higher up the same result. */
export declare const CIRCULAR_RESULT = "[circular result]";
/** Keys removed from every result object, whatever their value. */
export declare const EMBED_RESULT_SENSITIVE_KEYS: ReadonlySet<string>;
/** Keys removed from an object that carries an embed routing signal. */
export declare function isEmbedCredentialKey(key: string): boolean;
/**
 * Whether a URL's own path is the embed start route, which redeems a ticket
 * when loaded. It decides when to mint a session, which URL is the open link
 * and which start URL a view is handed, so it must not match a page that only
 * mentions the route. Model-visible output is checked more broadly, by
 * `redactEmbedCredentials` and `modelVisibleToolResponse`.
 */
export declare function isEmbedStartUrl(value: string): boolean;
export declare const IMAGE_BYTES: RegExp;
export declare const MAX_DECODE_ROUNDS = 8;
/** One string as every check below reads it. */
export interface StringReading {
    /**
     * The string and each layer of percent, JavaScript string and HTML escaping
     * under it, to `MAX_DECODE_ROUNDS` layers deep. Each layer also contributes
     * its control-free spelling for ticket discovery and echo matching.
     */
    layers: string[];
    /**
     * Whether every layer could be inspected within the decoding and reference
     * work limits. Otherwise no check here can say what the string holds.
     */
    complete: boolean;
    /**
     * Whether any layer carries a canonical embed URL/path or a ticket-bearing
     * relative embed reference. Ordinary route discussion and filenames survive.
     */
    mentionsRoute: boolean;
}
export declare function readString(text: string): StringReading;
/**
 * Text a model sees outside a result, such as an error message or a refusal.
 * The text is the whole output, so one that carries an embed reference or
 * cannot be fully inspected is hidden whole.
 */
export declare function redactEmbedText(text: string): string;
/**
 * A thrown value, or text built from one, as a server log shows it: its name
 * and message, hidden whole as `redactEmbedText` hides text. It is the
 * thrower's data, and reading it may throw too, so one that cannot be read is
 * named only as such.
 */
export declare function describeThrownForLog(error: unknown): string;