/**
 * Stable references for plugin secret settings.
 *
 * A settings response never carries a secret's value. Every secret leaf is a
 * marker instead:
 *
 * - `{ "$secret": "sec_…", "set": true }` — a stored secret, referenced by a
 *   stable opaque id. Send the marker back unchanged to keep the stored value.
 * - `null` — nothing stored at that position.
 * - `{ "$secret": null, "locked": true }` — the effective value comes from the
 *   environment and is never written back.
 *
 * On save each secret leaf accepts the reference, a plain string (a new value),
 * or `null` (clear). Payloads carry `secret_format: "ref"` so a `null` reads as
 * a deliberate clear rather than the deprecated "unchanged" placeholder.
 */
/** Reserved marker key that references a stored secret. */
export declare const PLUGIN_SECRET_REF_KEY = "$secret";
/** Reserved payload key declaring which secret wire format a client speaks. */
export declare const PLUGIN_SECRET_FORMAT_KEY = "secret_format";
/** Wire format published and understood by this SDK. */
export declare const PLUGIN_SECRET_FORMAT_REF = "ref";
/** One `$secret` marker as published by a settings response. */
export interface PluginSecretRef {
    $secret: string | null;
    set?: boolean;
    locked?: boolean;
}
/** What a settings form should tell the user about one secret field. */
export type PluginSecretState = 'set' | 'unset' | 'environment';
/** Return whether one settings value is a `$secret` reference marker. */
export declare function isPluginSecretRef(value: unknown): value is PluginSecretRef;
/** Return the stored secret id behind a marker, or `null` when nothing is stored. */
export declare function pluginSecretId(value: unknown): string | null;
/** Classify one secret field for display: stored, unset, or environment-provided. */
export declare function pluginSecretState(value: unknown): PluginSecretState;
/** Human label for one secret field's state. */
export declare function pluginSecretLabel(value: unknown): string;
/** Whether a secret field is read-only because the environment supplies it. */
export declare function isPluginSecretLocked(value: unknown): boolean;
/**
 * Value to submit for an untouched secret field: the reference, unchanged.
 *
 * A locked marker round-trips too, which is how the platform keeps a stored
 * value that an environment variable currently hides.
 */
export declare function keepPluginSecret(current: unknown): PluginSecretRef | null;
/** Value to submit when the user typed a new secret. */
export declare function setPluginSecret(value: string): string;
/** Value to submit when the user cleared a secret. */
export declare function clearPluginSecret(): null;
/** Whether a settings response declares the `$secret` reference wire format. */
export declare function usesPluginSecretReferences(response: unknown): boolean;