import * as smoltalk from "smoltalk";
/**
 * What Agency keeps in a smoltalk message's `metadata`: a debug label, and
 * when the runtime removes the message. This module is the only place that
 * spells the key names. See docs/dev/runtime/expiring-messages.md.
 */
/** Who owns an expiring message: the `llm()` call, the single model
 *  request, or the handoff dispatch that added it. */
export type ExpiresAt = "llmCall" | "request" | "handoff";
/** When the message is removed. `key` names the owner; it is null only for
 *  an `llmCall` message that Agency code pushed before the call started,
 *  which the next `llm()` call on the thread claims. */
export type Expiry = {
    at: ExpiresAt;
    key: string | null;
};
export type MessageMetadata = {
    label?: string;
    expires?: Expiry;
};
/** A change to a message's metadata: a key left out is kept, and a null
 *  value removes the key. */
export type MetadataPatch = {
    label?: string | null;
    expires?: Expiry | null;
};
/** The debug label, or null. */
export declare function labelOf(message: smoltalk.Message): string | null;
/** True when the role may carry an expiry: system or user. A tool message
 *  must stay paired with the assistant message that called it, and an
 *  assistant message with tool calls must keep its results. */
export declare function mayExpire(message: smoltalk.Message): boolean;
/** The expiry, or null for a message that stays with the thread. Null for a
 *  role that may not expire, whatever its JSON carries: a seeded message or
 *  an edited checkpoint can put anything there. */
export declare function expiryOf(message: smoltalk.Message): Expiry | null;
/** A copy of `message` with `patch` applied to its metadata. The copy is rebuilt
 *  through its JSON, so it is an instance of the same class, and the
 *  original is untouched: `adoptFrom` and `getMessages` share instances. */
export declare function withMetadata(message: smoltalk.Message, patch: MetadataPatch): smoltalk.Message;